Rotation is broken

[thikade]

Thanks for this great, nifty little piece of code!
After playing around with different rotation angles I noticed that rotation seems to be broken. I cannot get the 4 possible rotation angles to work, only 3 angles can be displayed.
Piece of code I am using:

    i = 0
    while True:
        unicorn.rotation(i)
        i = (i + 90) % 360
        # ... display something
        unicorn.show()                             
        time.sleep(0.8)