010   # magic increment preserves leading zeros
10    # treating it as a number doesn't give leading zeros
010   # but doesn't strip them from the scalar
11    # but the next increment is numeric not stringy
# stringy increment can deal with /any/ number of digits:
1234567890123456789012345678901234567890123456789012345678901234567891
# numbers only have about 20 significant digits:
1.23456789012346e+069
# treating as a number doesn't destroy the string:
1234567890123456789012345678901234567890123456789012345678901234567891
# but the next increment is just numeric
1.23456789012346e+069
0     # and adding 1 to 1e69 does nothing