Code Sketch

def shape() {
    left(90)
    repeat(8) {
        left(45)
        forward(25)
        right(90)
        forward(25)
    }
}
def block() {
    shape()
    right(45)
}
cleari()
setBackground(white)
setPenColor(black)
setAnimationDelay(0)
repeat(10) {
    block()
}