Bake cake according to package directions in 2 round pans (8 or 23 cm). Put one layer in bottom of punch bowl. Put 1 can vanilla pudding on top. Drain 1 can pineapple (reserve juice). Slice 3 bananas and dip in pineapple (reserve juice). Slice 3 bananas and dip in pineapple juice; place bananas on top of pudding. Put drained pineapple on top of bananas. Put second cake layer in next. Repeat with pudding, bananas and pineapple. Place 2 containers of sliced sweetened strawberries (thawed) on next. Top with Cool Whip and nut topping.