Before there was chess, there were rocks ... and bamboo!
When the Sims play, the piece that he holds in his hand will still be a chess piece, it will not be a rock.
This should look way better in your game... I am using the lowest graphics settings to test these as I am using a borrowed laptop for now. It has only been lightly tested.
"In The Beginning" Chess Table Beta
Table Converted from Sims Castaway Stories