def rotation=(val)
			permissible = [0, 90, 180, 270]
			fail ArgumentError, "invalid rotation, permissible: #{permissible.join(', ')}" unless permissible.include?(val % 360)
			@rotation = val % 360
			push_all_pixels
		end
def rotation=(val)
			permissible = [0, 90, 180, 270]
			fail ArgumentError, "invalid rotation, permissible: #{permissible.join(', ')}" unless permissible.include?(val % 360)
			@rotation = val % 360
			push_all_pixels
		end
Set rotation of the Unicorn HAT to +val+

 Permissible values for rotation are [0, 90, 180, 270] (mod 360).

 You still have to call +show+ to make the changes visible.