MK 61/54

Emulator of "Electronika MK 61" and "Electronika MK-54" RPN programmable calculators. Long-press 'list of active apps' button to enter menu. Hint 1: touch calculator's indicator to toggle slow/fast mode. Indicator's blinking looks better in slow mode. Hint 2: you can choose between MK-61 and MK-54 using menu option that becomes visible when calculator is switched off.