I see two issues not addressed by the other comments:
1) I would start with a 2x2 plate not a 2x2 brick. They are heavier per height, but I think they will also be much stronger because the weight is not supported by the sidewalls alone.
2) They didn't account for compression of the bottom bricks in their height calculation. If anyone is going to take them seriously they need to publish the strain at the yield point. Then we get to use some calculus to figure out the actual height!
1) I would start with a 2x2 plate not a 2x2 brick. They are heavier per height, but I think they will also be much stronger because the weight is not supported by the sidewalls alone.
2) They didn't account for compression of the bottom bricks in their height calculation. If anyone is going to take them seriously they need to publish the strain at the yield point. Then we get to use some calculus to figure out the actual height!