Examples

Draw a square:

forward 10
right 10
back 10
left 10

or:

4.times:
  forward 10
  turn right

Create a twisting tower:

var
  length = 20
  height = 50

height.times:
  left length / 2
  back length / 2
  4.times:
    forward length
    turn right
  forward length / 2
  right length / 2
  turn 5
  up 1

Draw randomly:

up 10
forward 10

(50..100).times:
  forward 2..5
  turn -180..180
  up 0..2

Set the color to blue randomly with a 1 in 50 chance. Otherwise set it to white:

if 1 in 50:
  color = blue
  
else:
  color = white

or as a one-liner:

color = if 1 in 50: blue else: white

Move forward 10 times, cycling through colors:

10.times:
  color = cycle(red, black, blue)
  forward 1

Draw a whole shape at once. A hollow box with a hole erased for a door is an instant house:

color = white
box 9, 6, 9, fill = false
box 2, 3, 1, at = vec3(4, 0, 0), color = eraser

See Drawing Shapes for box, ball, can, wall, and floor, or follow the Build a House tutorial to make one step by step.