The design is very nice but the key positions are quite unusual for a calculator. I would expect a layout with the keys 7-8-9 in the upper row. This NCALC version has not a calculator keypad but a phone keypad. How about a switch in the setup menu for both versions?

Ah I built deliberately to have a phone layout as there are already many calculators with calculator layout, and more people are coming from mobile phones than calculators now.