Some possible answers:
TO LOAF
REPEAT 180 [ FD 1 RT 1 ] {this is half a circle}
REPEAT 4 [ FD 50 RT 90 ] {size depends on circle}
END
First...
TO SQUARE
REPEAT 4 [ FD 50 RT 90 ]
END
Then...
TO LOAF
REPEAT 180 [ FD 1 RT 1 ]
SQUARE
END
