Review on Advanced Structures For Babies & Toddlers Ages 10 Months And Up - WEofferwhatYOUwant Super Ball Drop With Double Bridge & Spacers! by Troy Coste

The overall product is useful. You can stack them however you want and with the 4 heavy balls provided it does work. Better to use on a hard surface but it will work on a carpet. However, it is very flimsy and sometimes the balls do get stuck while rolling due to the unstableness. My kid does enjoy it but without my help he does get a bit frustrated and eventually gives up. So 90% of the time I will play this with him. I think its a bit overpriced for what you get and recommend something other than this unfortunately.