I remixed the Magnetopult Mark III by Ian Foulds so that it would throw Rocks even further!   I:

• Angled the front upwards.
• Added room for more magnets (24 total!).
• Removed the extra slots for positioning the crossbar.  There was so much force when using all 24 magnets that it would break the plastic between the slots when I tried to leave them in there.
• Extended the throwing arm axle slightly so it would not pop out.
• Lengthened the base and the throwing arm.