Piano Keys

My first interesting Context Free Design Grammar (CFDG) v2.2 creation. The code is below.

startshape PianoKeyes

rule PianoKeyes{
10*{r 36} Key {s 0.99 }
PianoKeyes {s 0.89 r 5}
}

rule Key{
TRIANGLE {size 6.75 0.25 x 10 y 0.75 rotate 94}
SQUARE {size 4.5 0.75 x 10 y -0.75 rotate 99}
}