What a concentration grid is
This page presents 100 shuffled targets labelled 00 through 99. In ascending mode the first target is 00; in descending mode it is 99. The leading zero is part of the label, so 03 remains 03. The activity is a number-order and visual-search practice tool, not a diagnostic test.
Difference from a standard Schulte Table
A standard 10×10 Schulte Table usually contains numbers 1 through 100. This grid instead contains the strings 00 through 99, so the target labels and endpoints differ. Histories use a separate concentration-grid mode to prevent these tasks from being mixed.
Full completion and timed challenge
Full Grid continues until every target has been found and saves completion time and mistakes. One-Minute Challenge stops after 60 seconds and records how many correct targets were found. Challenge results should be compared with earlier attempts in the same direction, not with a population category.
Coach mode
Coach mode runs the full sequence but hides the changing timer until the round finishes. This can help when watching elapsed time is distracting. Error flash can also be disabled, while a text mistake count remains available so state is not communicated by color alone.
Interpreting personal results
Review found count, completion time, mistakes, and seconds per correct target together. Input method and screen size can noticeably change a 100-cell interaction. Compare the same mode and direction across several attempts, and use the progress tracker for a longer trend.
Device and input limits
The grid scales to the viewport, but very small screens produce smaller targets than a desktop display. Touch, mouse, and keyboard interactions also differ. Multi-touch and rapid repeat activation are guarded, yet deliberate single taps or keystrokes give the clearest record.
Printing and scope
Print mode uses your browser print dialog and hides navigation, controls, results, and explanatory sections. The current shuffled grid is fitted for common A4 and Letter pages without a server-generated PDF. The activity is not a medical, vision, or attention assessment and makes no treatment claim.