Thanks for writing in! I actually ordered used/dirtied baseballs from sellers online - various ones from all over in as large of quantities as I could get. Then my husband made a plywood back and wood frame (miter cut boards) and we painted it all the same color as the walls. Then I mapped out a grid on the back side to make sure it was spaced correctly - I used AutoCAD, but simply measuring would work too. Then I held the ball on the front while he used an electric drill to screw into each ball - as I held them. It took a while, but was very worth it!

that's fantastic! thank you so much for sharing your creativity