Alternating token sequence
Find number and letter tokens by one explicit rule: 1, A, 2, B when numbers start, or A, 1, B, 2 when letters start. The full token sequence—not only one token type—is reversed in Reverse mode. Token labels and borders distinguish the two types without relying only on color.
Alternating token sequence
1 → A → 2 → B → 3 → C → …
Final token: number 13
Screen, input, settings, pauses, and familiarity affect results. This is not an ability or health score.
No completed attempts yet.
This is a rule-based visual-search practice. It requires alternating between two token types, but its result does not measure or diagnose attention, task switching, executive function, reading, or health.
The sequence builder creates one token for every cell. Numbers begin at 1 and letters begin at A. Numbers First alternates number then letter, while Letters First alternates letter then number. The displayed letter case does not change a token’s stable identity.
Numbers First begins 1, A, 2, B. Letters First begins A, 1, B, 2. Both rules use each generated token once. The current target always names its type as well as its displayed value.
A 3×3 or 5×5 grid has an odd number of cells, so the starting type also supplies the final token. For example, a 3×3 Numbers First sequence ends with 5, while Letters First ends with E. View Full Sequence shows the exact ending before a round.
A 6×6 grid needs eighteen numbers and eighteen letters. This remains inside A–Z. Larger alternating grids could require multi-character letter tokens, so this basic mode stops at 6×6 instead of adding AA or AB.
This page changes token type after every correct choice. A number-only table follows one numeric order, while the letter table follows one alphabetical order. Use the links below when you want a single token type rather than an alternating rule.
Preview the rule, select the current target, and use Hint when needed. A wrong choice adds one mistake but does not advance the sequence. Untimed practice remains available, and a faster result with more mistakes is not treated as automatically better.
Completion time, seconds per cell, and mistakes describe this browser task only. Screen, size, case, direction, input device, familiarity, pauses, and distractions all affect a result. Personal bests compare only identical configurations.
The complete generated token list is reversed. For Numbers First 1, A, 2, B, the target order begins with the original final token and continues backward through both numbers and letters.
No. It changes letter presentation only. Stable IDs and A–Z data values remain unchanged.
This tool deliberately supports 3×3 through 6×6 so alternating tokens remain within single letters A–Z without AA-style extensions.
No. The latest ten records and settings remain in localStorage. The optional Tracker action also stays in this browser.