Lay ten matches side by side (Fig. 7) and request some one to lift each
match singly, and passing it over two matches, cross a third match with
it until there are five crosses on the table (Fig. 8). Two matches (and
only two whether crossed or single) must be passed over at a time.
1 2 3 4 5 6 7 8 9 10
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
Fig. 7.
\ / \ / \ / \ / \ /
\ \ \ \ \
/ \ / \ / \ / \ / \
Fig. 8.
The secret is that No. 1 must be crossed first and No. 9 second, or the
trick cannot be accomplished.
The following are the correct moves: 4 over 2 and 3 and crossed on 1; 6
over 7 and 8 and crossed on 9; 8 over 7 and 5, crossed on 3; 2 over the
3 and 5, crossed on 7; the 10 over the 9 and 7, crossed on 5.