One board. One wall. Two of you.
The board is eight columns by sixteen rows, laid out between your two pairs of hands. The wall splits it: you own the rows on your side, they own theirs, eight each to start. Each of you holds three pieces, dealt from the same sequence, so the luck is equal. Use all three and three new ones come.
There are no turns. You both play at once. A row full across your half clears, and so does a column, if it's full from your edge to the wall. Every line you clear shoves the wall one row into their half, and whatever they had in that row shatters. Clear several at once, or on drop after drop, and it shoves further.