The Penrose Triangle is what's known as an "impossible object." You've probably seen some of these before (Penrose is second from left):
Now, designer Martzi Hegedűs has designed a typeface in which every character is an impossible object. It's beautiful, but it'll give you a headache in 20 seconds flat. Via JeannieJeanni:
The font's special characters are like aneurysm delivery mechanisms.
Pretty good way to spice up the PTA bulletin, I think.