Tablet Stand for Keychron K3 Keyboard

If you print two copies of this, you can add a tablet stand to a Keychron K3 keyboard. The few advantages of this over a standalone tablet stand are: 1) standalone tablet stands which allow you to also rise the tablet up instead of just leaning it on something (which is relatively bad in terms of ergonomics) typically take up more spaces as it needs a larger base to stabilize itself, but I think the weight of the keyboard can already do that job; 2) It is easier to move the keyboard and the screen around or put them on a soft surface like on the bed or on the lap because they are attached to each other. I have just managed to work on an iPad by streaming the screen of my PC at home to it with Sunshine and Moonlight during a bumpy ride in an inter-city bus. I had a small table just enough for my keyboard and a mouse and it turns out they hold up fairly well except that without a mechanism to fix the tablet to the stand, there is a risk that the tablet slides around or even fall off when the bus is making hard brakes or sharp turns. For now this design still have many flaws and hopefully I can fit them in next iterations, e.g. the weight of the tablet will be too much for the clamp-on bracket if you use the built-in riser of the keyboard because in that case the stand is not supported by any surface and you are solely depending on the stiffness of PLA to combat deformation, so I am making a variant that comes with a riser such that you can use that instead.