A grid of moving rectangles

RectangleGrid.py

# Inspired by:
# https://www.instagram.com/p/_hZD9hn9Xn/

def square(x, y, size, phase):
    turns = phase // 2
    q = (phase % 2) / 2
    with savedState():
        translate(x, y)
        scale(size)
        rotate(-90 * turns, center=(0.5, 0.5))
        rect(0, 0, 1 - q, q)

canvasSize = 500
nSquares = 8
squareSize = canvasSize / nSquares
nFrames = 80

for frame in range(nFrames):
    framePhase = 8 * frame / nFrames
    newPage(canvasSize, canvasSize)
    frameDuration(1/20)
    rect(0, 0, canvasSize, canvasSize)
    fill(1)

    for i in range(nSquares):
        for j in range(nSquares):
            phase = 2 * (i + j) / nSquares + framePhase
            x = i * squareSize
            y = j * squareSize
            square(x, y, squareSize, phase)

saveImage("RectangleGrid.gif")