Naturally, I also had to add an #include for BlitPixieScaled.h, and add BlitPixieScaled.c to the project.
You can control how large or small the sprites are scaled by changing kMinSpriteSize and kMaxSpriteSize.
The demo is more interesting if you paste in the picture of a teddy bear included in the Scrapbook that comes with System 7.5 or later. Just copy it and paste it into PICT resource 128 of the demo and Simple.π.rsrc.
If the 68k version runs slowly, you can turn off the large idle Sprite and decrease the number of bouncing balls. You can also lower the maximum size of the balls.