Anki Cosmo back plate

I started the play with my cosmo after I found a palette and palette fork for him here https://www.thingiverse.com/make:462003 I also made the forks longer so the pallet wouldn't fall off I will post the design. but as I was playing with him I realized he didn't have enough weight in the back but could still pick up what I had in the pallet. so I taped a roll of electrical tape on him. it has worked fine so far but I wanted something more professional. so I made this one late night.