Code Sketch

def shape() {
repeat(1) {
    forward(100)
right(95)
forward(100)
repeat(4) {
        forward(100)
        right(90)
    }    
}
}
 def block() {
    shape()
    right(10)
 }
clear()
setBackground(white)
setPenColor(black)
setAnimationDelay(0)
repeat(180) {
    block()
}
invisible()