width w means the puzzle
is w characters wide.
height h means the puzzle
is h characters high.
rows define the rules for each row,
starting at the top and moving down.
columns define the rules for each
column, starting on the left and moving right.
Note that rows or columns containing no solids in
the puzzle have the rule ‘
0’ — blank
lines are ignored.
maxrule is obsolete and
Arbitrary properties can be specified, e.g.:
a copyright notice
the position in a collection
HTML character references or entities, e.g.,
é for é, should
be used for non-US-ASCII characters.
The string may be quoted. The quotes do not form
part of the string itself.