"The screen and keypad were always meant to be the main feature of this machine," he writes on YouTube. "The main display boasts 25 digits. Square root signs are displayed and can change to accommodate any number of digits. Square root signs, add, minus, multiply and divide signs are displayed at appropriate times, and there is a full fraction display.
The 7-segments for the fractions are the smallest possible, being only 3 wide, and stackable vertically and horizontally." The video itself explains that its overall size is more than 5 million cubic meters -- just over 250 x 250 x 100 blocks. It provides 14 functions, BCD input, 2 BCD-to-binary decoders, 3 binary-to-BCD decoders, and 6 rapid BCD adders and subtractors. It also contains floor after floor of live decoders for quick conversions, a 20 bit (output) multiplier, 10 bit divider, a memory bank and additional circuitry for the graphing function.
Source: Toms Hardware