4×4 MEMORY · 15 ROUNDS
Remember the square that flashes, then select its hidden position.
Complete 15 rounds. The flash gets shorter every five rounds.
READY?
Use QWER / ASDF / ZXCV / UIOP, or tap a square.
Keyboard rows: Q W E R · A S D F · Z X C V · U I O P
Touch or mouse: select the remembered square
HOW TO PLAY
Start a round and watch the 4×4 grid. One square will flash briefly.
After the flash disappears, select the same square by touch, mouse, or its displayed key.
Standard lasts 15 rounds. Endless ends on the first wrong answer or timeout.
VISUAL WORKING MEMORY
The task combines brief visual encoding, spatial working memory, and choice reaction. The target vanishes before input begins, so you must retain its location instead of following a visible cue.
Shorter flashes make encoding harder. A shrinking answer window in endless mode also pressures retrieval and response selection.
READ YOUR RESULT
Reaction time begins when the flash disappears. The average uses correct answers only, while accuracy includes wrong answers and timeouts.
For a useful comparison, keep the same screen size and input method. Larger screens change the distance your eyes and pointer must travel.
QUESTIONS
It starts when the highlighted square disappears and the grid is ready for your answer. The flash viewing time is not included.
The four rows are QWER, ASDF, ZXCV, and UIOP. Every square displays its key. You can also use Tab to focus a square and Enter to select it.
The flash becomes shorter and the answer deadline shrinks as your streak grows. One wrong square or timeout ends the run.
Yes. Tap the remembered square directly. The 4×4 board scales to fit small screens without horizontal scrolling.