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How do you generate random patterns and convert them to an image?

I am currently making a game. I have multiple users and for each user I have a id (UUID). I was hoping to use this id as like a key to generate a random pattern then to a image for that player.
boolean[] booleanPlayerID = BSUtility.bytesToBooleans(playerID.getBytes(UTF_8));
WritableImage image = new WritableImage(50, 50);
PixelWriter writer = image.getPixelWriter();
int booleanIndex = 0;
for(int y = 0; 50 > y; y++){
for(int x = 0; 50 > x; x++){
if(booleanIndex >= booleanPlayerID.length){
booleanIndex = 0;
}
if(booleanPlayerID[booleanIndex]){
writer.setColor(x, y, Color.BLACK);
}
booleanIndex++;
}
}
Assuming the image is going to be 50x50... What I have been doing is I take the player's id, convert to boolean array, cycle through image pixels, also cycle through boolean array, if the boolean value is true then set the pixel color to black. The if statement is to avoid indexing out of bounds (I know I should probably convert the boolean array to be the same length as how many pixels are in the image)...
This does produce some what of a pattern, but to be honest it is a really shitty pattern. The patterns generally tend to be very similar to one another. I was wondering if someone could provide tips/example of how to do this better. With my little research I really couldn't find much. I did however find patterns that I am hoping to somewhat obtain, I believe they are called tangle patterns. I would really hope to have each user have their own unique image/pattern but obvious it is fine if they are somewhat similar but not same. I don't know if this is possible to be honest.
If you need a complete example I can replace the code above. Although the code above should be pretty straight forward to making it a full example (only things missing is generating the userID and converting it to boolean array from bytes).

What you are talking about is known as IDENTICON.
I actually don't know how they work but i know that they use some sort of hashing with the UNIQUE TEXT and generate image with that hash.
Here are two website i found who do provide source code so if you are interested you can look into the code and extract any useful information from there.
http://identicon.net/
https://jdenticon.com/
PS. Code are in JavaScript and on one website its in .NET and PHP too.

Neural networks and Python

I'm trying to study about neural networks, following a great guide:
http://neuralnetworksanddeeplearning.com/chap1.html
Currently I've reached this code snippet which I'm trying to understand and write in Java:
class Network(object):
def __init__(self, sizes):
self.num_layers = len(sizes)
self.sizes = sizes
self.biases = [np.random.randn(y, 1) for y in sizes[1:]]
self.weights = [np.random.randn(y, x)
for x, y in zip(sizes[:-1], sizes[1:])]
I managed to figure out what everything means except for the last line:
[np.random.randn(y, x) for x, y in zip(sizes[:-1], sizes[1:])]
As far as I can understand: create a matrix with y rows and x columns, for each pair x,y which can be found in the matrix zip which is created by the merging of the two "sizes" arrays. I understand that sizes[1:] means taking all elements from sizes starting from index 1, but sizes[:-1] makes no sense to me.
I read online that s[::-1] means getting the reverse of the array, but in the above case we only have one colon, while in the formula for the reverse array there seems to be two colons.
Sadly, I have no idea how Python works and I got pretty far along with the online book to give it up now (I also truly like it), so can someone say if I'm right until now, correct me if needed, or straight out explaining that final line?

sizes[:-1] is a list slice which returns a copy of the sizes list but without the last item.

Searching a matrix for a chain of sums

I'm still trying to improve on my coding skills, and this question has got me spinning in my tracks a little bit, so any help is greatly appreciated. I know how to create the random array very easily, no problem with that. However, the logic of finding the chain is proving very difficult for me. I believe the proper approach is some sort of depth first searching algorithm, but I'm not entirely sure of how to implement that in this scenario, or whether that is even correct.
My basic question is, should I be using depth first search, and if so, should I be doing it recursively? Any tips or hints on implementation are also welcome!
Make a program that creates a 3x3 grid of random
positive numbers where 0 <= n <= 9. The program should
find all possible combinations of numbers that add up to the area of
the grid, or 9, using these rules (similar to Boggle):
a. The numbers must be "chained" in sequentially adjacent cells, where
"adjacent" cells are those horizontally, vertically, and diagonally
neighboring
b. The chain does not have to be in a line. For example, it could go
horizontally once, then vertically once, and finally diagonally once
c. At least the “grid width - 1” cells must be used in the chain (a
3x3 grid means that at least two cells must be used)
d. A chain cannot repeat a grid cell that it has already used
e. Chains that use the exact same cells as a previous chain are
considered repeats and should not be counted
I know that for each element, when you are searching through each adjacent element, you must check and keep track of whether it's been visited before, so you don't repeat numbers.
public class GridSolver {
int[][] workingGrid;
public GridSolver(int[][] workingGrid){
this.workingGrid = workingGrid;
}
public String solve(){
int length = this.workingGrid.length;
boolean[][] visited = new boolean[length][length];
for(int rows=0; rows<length; rows++){
for(int columns=0; columns<length; columns++){
if(visited[rows][columns] == false){
dfs(workingGrid[rows][columns]);
}
}
}
return null;
}
public HashSet<ArrayList<Integer>> dfs(int element){
HashSet<ArrayList<Integer>> chains = new HashSet<>();
checkLeft();
checkTopLeft();
checkTopMiddle();
checkTopRight();
checkRight();
checkBottomRight();
checkBottomMiddle();
checkBottomLeft();
return null;
}}
This is what I have so far and I realize that it is pretty sloppy and not the best thought out scheme, but that's why I'm here I guess :P.
Also just to explain some of my thinking in the code, the dfs()method has a return type of HashSet because I know that you can't have duplicate chains, and it is a set of a list of the chains. Also the "check" methods are not implemented, I just wrote them down because I know that you will need to process each of these adjacent blocks for each number.
Once again, any help is greatly appreciated, and thank you for humoring me as a beginner here!

Connect Four Program using 2D Arrays in Java

These are the specs for the program I need to complete. Could someone please help me!! I really need to get this program done! Will take any help/advice I can get! Thank you all so much!
You must create two programs named Board and ConFour that have the
following criteria:
1) Proper Introduction
2) Comments that accurately describe the program features
3) Board should have one attribute; a two dimensional array of
character values representing the Connect Four game board. Be sure
to include a constructor (without parameters) that instantiates the
2D-array with 6 rows and 7 columns
4) Board should contain at least four methods. The first method should
be setBoard() which adds an empty character value to every position in the board. The second method, setPosition(), should place the character representing a player (X or O) in the column of their choosing. The third method named checkWinner() should check the board to see if there are four of the same character (X or O) in a row, column or either diagonal. Lastly, printBoard(), should print the contents of the board.
5) ConFour should represent the game play. Have the user(s) enter
START to start the game (they should be able to continuously play after each game)
6) Start each turn by printing the board followed by asking the user to
enter the column they want (be sure to alternate players). If the user enters an incorrect column number, make them re-enter. First player to get four in a row, column or either diagonal is the winner.

Here is a little bit of my thoughts:
To start off, try to make algorithms that check for 4 Xs/Os in a row, which should be 4 for each player. You could also just make 4 algorithms that require you to input the number you are checking for. The directions you need to check are horizontal (check array[i][x+1], where i is the constant in the for loop and x is the number you find to be X or O), vertical (check array[x+1][i] ), right-facing diagonal (check array[i+1][x+1] ), and left-facing diagonal (check array[i-1][x-1].
To print the board, just use 2 for loops that print the values of the array.
For the intro, use a bunch of System.out.println() statements.
The entering of coins is the weird part. You have to create height variables (Or a height function) that stores/checks the height of the coins, then places it on top/next to the other coin. Then check if anyone wins and move on the next player. Keep repeating it until someone wins. Warning: Do not use a while loop. They can't check more than one boolean at a time (but you could put a bunch of if(check) {
boolean itsalltrue = true;
}s, too.
Well, that's all that I can think of (I deliberately did not write the code because I would like you write your own). Enjoy!

Is this for a class? Did you literally just copy and paste the assignment? Try spending some time looking through the notes provided for you, or search more specific questions here. Here's an example of a similar question with code:
Simple 2d array java game

longest path in a maze

i have an assignement to find the longest path in a maze using recursion. i also have to show the process of searching for the path. I think i get the idea of how its supposed to be done but i get myself into truble when it comes to the code. Now i don't want the code done for me. I just need some pointers and some tips on my logic. . this is my recursive method so far. I guess there is no point sharing the graphics methods since the recursive method is where im stuck at.
void findPath(Point a){ // starting point
if (a == mazeEnd){
pathAdd(a);
return;
}
if (wall(a)) return;
if (visited(a)) return;
if (a == mazeStart) pathAdd(a);
length++
printPath;
findPath(new Point(a.x+1, a.y));
findPath(new Point(a.x, a.y+1));
findPath(new Point(a.x-1, a.y));
findPath(new Point(a.x, a.y-1));
}
UPDATE: ok thank you all for the tips and let me further explain. the entire board is a grid. i read the walls, starting and enting point from a file. i create a list for the walls and palce them on the board. wall(a) checks if a coordinate is the walls array. pathAdd is a method taht adds a coordinate to the path array. but doesnt that means that after it has complyted all the paths, the path array will have every coordinate in that board except the ones that are walls? At least in the wway i have coded it. Thats my major issue i think. If i can get the list to only hold one path i guess ill figure out how to get the largest out of it.

There's a few omissions I see.
You never add the current point to your path - you only ever add the start or the end.
You never mark any points as visited.
You check to see if things are visited, but you don't have a way of knowing if they were visited in this path or some other path. Consider the scenario where there is some islands of walls, and you could reach a point via two or more routes: one of those routes may be longer than the other routes, but you're more likely to reach it via the short route first. It will end up being ignored, when it should be considered as a candidate for both routes.
You are triggering length++ on every call to find path. If you do your first node, and then the 4 nodes around it, you're going to have a length of 5 when your longest is 2. That's no good!

If you passed a list into the method, when you found a path that made it to the end of the maze, you could add it to the list. then when recursion finishes, you can iterate through the list to find the longest path.

You are restricting to move further when a cell/point is visited. But I didn't see you marked a cell/point as visited in your code. You can do this just before moving into the four directions. If you do not do this, your recursion will never get an end.

findPath(a) should return a length. Specifically it should return the max(findPath(up) || findpath(down) || findPath(left) || findPath(right)) + 1. If wall(a) or visisted(a), you can return a large negative number and for mazeEnd(a) return 1. To print the path you need to add the new Point that returns the greatest length with pathAdd(). Hope that helps :)