Nothing complicated here, except maybe the audio seems weird. I'm going to try using an H bridge for differential output. Combined with two R2R ladders it gives 5 voltage levels, so ~2.3 bits of resolution.
The main visual inspiration is the OP-1 synthesizer from Teenage Engineering.
So there are 4 dominant squares, one for screen, one for speaker, and two for the buttons. The icons will be silkscreened in black and red. The OP-1 is aluminum but I'm going to work in Delrin for the body. It's what I have on hand but it's also nice on the eyes and to the touch.
Right now all I know is that besides basic support for reading the buttons, drawing on the LCD, and synthesizing audio, there will be a programming language for the user to use to orchestrate the parts. And I know it's all got to fit in 1 kilobyte because I want to submit this for the 1KB challenge.