Letter Mutations

Track a sequence of letters through a series of mutations and pick the final result.

How to play

You'll see a starting sequence of letters and a numbered list of mutations — like moving a letter to a new position, swapping two positions, or reversing a stretch of the sequence. Apply every mutation in order, then pick the letter sequence you end up with.

Apply the mutations one at a time, in the order listed — don't skip any.
Mutations act on positions, not on specific letters, so re-check positions after each step.
The wrong options are close to the real answer, so work through every step carefully.
Choose your difficulty before starting — higher difficulty means more letters and more mutations.

Why this matters

Applying a chain of positional transformations to a memorized sequence is a compact version of the mental manipulation required by working-memory tasks like the Letter-Number Sequencing subtest on the Wechsler scales, where holding and reordering items in mind — not just storing them — is what's being measured. Read more about the Wechsler Adult Intelligence Scale (WAIS).