Draw/plot a heart graph
TI-80 BASIC, 45 43 41 39 bytes
LBL 1
RAND4-2-&gt;X
RAND4-2
IF (X²+ANS²-1)³&lt;X²ANS³
PT-ON(X,ANS
GOTO 1


This took a while, and my battery is low so I didn't want to keep going.
I tried to use the second equation, but couldn't get it to work it actually turned out to be longer, so I just adapted the other answer I had.
EDIT: I just noticed the 50x50 pixel requirement, unfortunately the screen is only 47 pixels high so this isn't possible.