An edition of three, built from the circuits extracted from Speak & Maths.
They are (from the left): Math^index, Math, and Math⁰³.
They feature custom-painted enclosures, a 6 position multi-switch to choose which of the 5 Speak & Math "games" to play (Solve It, Word Problems, Greater Than/Less Than, Write It, Number Stumper, and the last position used to mute the sound), a momentary looper/glitch button (when momentarily pressed, whatever sound is heard will play as a sorta 4-bar loop), a human contact resistance point, an optical resistor, and a DPDT toggle switch to choose which state to play (loopy-glitch (left), Normal, or optical (right)). In optical mode, it dumps its ROM phrases, phonemes and tones, making for some very interesting continuous noise. In addition, thru the clear window can be seen the LED display, which displays the name of the game setting in normal or loop mode, and in optical mode, plays a little glitched-out LED movie, the characters and random bits of light controlled by light and voltage. Very neat!
The gadget will play itself for many minutes in proper lighting conditions, with subtle control over changes by using your hand shadows or a pocket LED light. It is very volatile (prone to crashing) in optical mode, thus the necessary red reset button on the front.
The notch cut out of the side is for wallwart or battery pack power access, and 1/8" minijack out. The bottom of the gadget has a speaker grill pattern drilled with the speaker mounted above and within, and tiny rubber feet to elevate the unit, allowing the sound to come out of the bottom of the gadget, resonating off the surface it sits on, effectively using tabletops or other surfaces as amplification.
You can find a few construction shots here, for those of you that are into that sort of thing.

Math^index: Owned by Boy-Genius Peter Washburn (index) of The Univac Index, God's Grandparents, Modrn Univac, and some time Big City Orchestra conspirator. Given as Birthday gift. Nice!

Math: Owned by me (univac). I put it thru its paces regularly and irregularly.

Math⁰³: Was for sale or trade. Has been committed to by Rob of Big City Orchestra.