Slide another bag over the open end of the first bag. An Adult can tape around the seam with sturdy tape, such as packing tape or wide masking tape. Create a large pile of the blocks. When the group of architects have completely agreed it is time, the building project can be knocked down. As a further step, the blocks can be broken down and readied for recycling when they are no longer needed for building.
Variations Use lunch bags instead of grocery bags for small blocks.
Combine other blocks in the building experience.