Since I can't edit the comment above anymore; I thought of another thing: you could use a combo of permanent and electropermanent magnets with a magnetometer t

Since I can't edit the comment above anymore; I thought of another thing: you could use a combo of permanent and electropermanent magnets with a magnetometer to make buttons on a surface that are flat across the surface when the device is off, and that raises up to a specific distance when switched on (like the polymagnet spring example that when rotated becomes attractive like a regular magnet). Then you also adjust the magnetism so that at a given distance you can feel a "click" feedback when you push the button down. You could even have controllable variable resistance and click depth, depending on what you're doing. A gaming mode, a typing mode, a casual mode, etc... No need for mechanical switches and buttons, just an attachment to hold the buttons in place. So you could have a completely flat folding keyboard that then has the buttons raise up like on a standard keyboard, feeling like a standard keyboard, yet with 10x the longevity. Better yet: make a surface with an array of electropermanent magnets and magnetometers, let each key have a Qr code like magnetic pattern with "magnetic anchors" plus a key identifier, and then you can place arbitary keys in arbitary positions to make yourself a keyboard looking however you want with no other manual work than key placement! You could even have keys that can rotate or slide and even have switches, and the keyboard's magnetometers would identify the key patterns and your computer would download the instructions for parsing the inputs from that key.