Haven't read comments yet but I just now excitedly `lightbulbed a MAFIK ][', that seems simple and completes the `other side': a tactile terminal, seems obvious, so I apologize if this is redundant. Billions of free recycled tiny motors tipped w/ eccentric cellphone vibrators at different freqs, if audible some other silent buzzer/solinoid/..piezo(flat form factor..input also?!), smaller earbud's speaker elements, per finger contact. Variable freq each buzzer may also equal entire space of chording combos. Serves deaf/blind equally well.