Interesting table.

In the Soviet Union there was a table for testing of observation. Its name - "Entertaining table».
 Look on the table sequentially numbers from 1 to 90 inclusive.
If you find them for 5-10 minutes, then you have an exceptional observation.
For 10-15 minutes - good.
15-20 minutes - the average.
20-25 min - satisfactory.


See also

New and interesting