If you’re not familiar with layers, the best way to describe them are ‘multiple shift keys’. Keyboards already have multiple layer keys:

• shift
• alt
• ctrl
• cmd

Basically it’s a key that when pressed in combination with a second key makes that second key return a difference value to ‘normal’. As keyboards get smaller, the simplest way to accommodate things is to add additional layers - a layer for numbers, and then you can remove the dedicated number keys; a layer for arrow keys and then you can remove these too.

You then get more complex with one-shot keys, home row mods, tap-dance etc.

I’ve been using a 36-key keyboard for a year or so now, and wouldn’t go bigger. Currently waiting on a PCB to be printed that is 24 keys. Will be interesting to see how I go with that one!

Didn’t mean to mark it as 18… I’ll see if I can fix it.

You’re right: Layers are essential. I use three primary layers – colemak dh, numpad, and nav – along with several combos. Another key feature is what are called Callum-style mods, which are essentially “sticky”, one-shot modifiers.

I’ve been using this layout for quite awhile now, so I’m pretty used to it. It took a month or so to switch from qwerty to colemak, but the switch to ortholinear (like this one) and column-staggered took under a week. Switching to home-row mods took a day, and switching from those to Callum took about a week.

Just some black acrylic. Not my idea, but I’d have to go diving through reddit to find the original.