Question 563477
Count {{{ 1 }}} for the 1st corner where you start.
Count {{{ 21/3 = 7 }}} to get to the next corner
Count {{{ 7 }}} to get to the 3rd corner
Count {{{ 7 }}} to get to the 4th corner
The 5th corner is where you started,
so only count {{{ 6 }}} to finish
{{{ 1 + 7 + 7 + 7 + 6 = 28 }}}
There are 28 posts