Wall & Cube

With a for loop, we were able to build an entire row of blocks with only two lines of code. What if we need to build a wall? We can certainly copy and paste that for loop multiple times. But a better solution would be to use nested for loop. How about a 3D cube? Just add another layer of loop!

To build a 2D wall, we need to loop through two directions: use i to iterate through x locations and j to iterate through y locations.

Brick wall:

// Build a 5 x 10 (width x height) wall
for (let i = 0; i < 5; i++) {
    for (let j = 1; j < 11; j++) {
        game.setBlock(new Position(i, j, -15), 17);
    }
}

Cube:

To build a 3D cube, we need to loop through three directions: i -> x, j -> y, k -> z

for (let i = 0; i < 5; i++) {
    for (let j = 1; j < 6; j++) {
        for (let k = 0; k < 5; k++) {
            game.setBlock(new Position(i, j, k - 20), 18);
        }
    }
}

Exercises:

Please try the follow two structures:

// line of yellow columns
for (let i = 0; i < 30; i += 4) {
    for (let j = 1; j < 10; j++) {
        game.setBlock(new Position(i, j, -10), 59);
    }
}

// brick stairs
for (let i = 10; i < 20; i++) {
    for (let k = -10; k < -5; k++) {
        game.setBlock(new Position(i, i-9, k), 17);
    }
}

The picture of the wall, cube, yellow columns and the brick stairs:

Challenge

Here is a challenge project. Try to figure out how to build the structures in this picture:

Answer example:

// black sheet
for (let j = 0; j < 10; j += 2) {
    for (let i = -j; i < j+1; i += 2) {
       game.setBlock(new Position(i, j+1, -20), 1);

// blue array 
for (let j = 0; j < 10; j += 3) {
    for (let i = -j; i < j+1; i += 3) {
        for (let k = -j; k < j+1; k += 3) {
            game.setBlock(new Position(i, j+1, k), 45);
        }
    }
}