A bitwise puzzle tower
High in a tower made of logic gates lives a wizard who knows exactly one spell: the exclusive-or. Point it at a row of runes and every rune it touches flips, dark to light, light to dark. Cast it twice and it undoes itself. That's the whole trick. It is a very good trick.
Make the runes match the seal. Each spell flips the runes it touches. Order doesn't matter, and any spell cast twice cancels itself out, so there's always a way back. Try to open each seal in par.
Seal I
Runes
Seal
| rune | spell | result |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
Different makes light. Same makes dark. That's XOR. It's how a computer adds without carrying, how a cipher hides a message and finds it again, how a game remembers which tiles you've flipped, and how a single parity bit can tell that something went wrong.
The tower teaches it the way a good puzzle teaches anything: you stop thinking about the rule and start seeing it. By the eighth seal you're doing binary in your head. You may not notice. The wizard will.
Curiosities in the tower: 0 of 0
Apprentice of XOR. You found everything in the tower. If the full spellbook happens, apprentices will get the bonus chapter of impossible seals.
A hundred seals, new spell types (shifts, rotations, the dreaded AND), a daily seal and a classroom mode. Tap what you'd actually pay for. Nothing is charged; this tells us what to build.
We'll write when the full spellbook opens, and occasionally with a new seal to solve over coffee.