Rose Patterns in DrawBot

newPage(1000, 1000)

# grid is defined by dimension of a single cell
cell = 80

rows = int(height() / cell)
cols = int(width() / cell)

offset_x = width() % cell / 2
offset_y = height() % cell / 2
translate(offset_x, offset_y)

pi_2 = 2*pi
rad = cell * 0.45

for row in range(rows):
    for col in range(cols):
        for a in range(int(100*pi_2)):
            save()
            fill(0)
            # move to center of single cell
            translate(col*cell + cell/2, row*cell + cell/2)
            rx = cos(row * a)
            ry = cos(col * a)
            x = cos(a) * rad * rx
            y = sin(a) * rad * ry
            oval(x-0.5, y-0.5, 1, 1)
            fill(None)
            stroke(.25)
            # rect(-cell/2, -cell/2, cell, cell)
            restore()

# accepts other filetypes, e.g. '.pdf'
saveImage('~/Desktop/roses.jpg')

See Daniel Shiffman’s Coding Challenge #55: ‘Mathematical Rose Patterns’.
Script will work in DrawBot.