cushioned floor mat for baby
https://nova-wiki.win/index.php?title=Enough_Already!_15_Things_About_50x50_Playpen_Mat_Foam_Thick_We're_Tired_Of_Hearing
Inspect your mat regularly for indications of wear such as threads falling loose, or damaged foam. Repair or replace if you find it necessary. Always keep it in a dry place to prevent the risk of developing mold.