Alot of you have probably seen some binary calculators out there on youtube. But this one owns them all!
It's an amazing construction where you even can get negativ numbers. You can choose wheter you want to add or substract numbers from the upper row with the lower row. And if you for exampel substract 4 by 6 you would get -2 as the answer.
The biggest problem I see in this is that if you choose to add 2 with 9 that would give 11 as the answer, and the display aint configured for that. But other then that it's an Epic construction!
And while we are talking about calculators I just found this on youtube. It's a calculator that uses minecarts as "numbers". It's not very practical since it's big and not very user friendly, but I belive it's a very inovative build, and that's always appreciatead and interesting!