# Monopoles

## Joseph DeVincentis (stacking idea suggested by Mark Halpin)

This puzzle consists of several Magnetic Monopoles puzzles, a variant of the well-known magnet puzzle created for the 2007 USPC by Adam R. Wood.

The flavor text helps you understand the basic rules here: each 1x2 rectangle in the nine grids is to be filled in with a dipole magnet (positive on one end, negative on the other) in either orientation, or left blank. Each 1x1 square is to be filled in with a magnetic monopole (positive or negative), and CANNOT be left blank. The normal magnet puzzle rule also applies: two like charges can never touch along an edge (touching on a corner is OK). The numbers around the edge tell you how many positive or negative charges are in a row or column. Just enough numbers are given in each puzzle to make the solution unique.

First, solve the nine puzzles. Then, as suggested by the flavor text and the repeated field strength values (including upside-down ones), stack the grids following the magnet adjacency rules, rotating and/or flipping the grids as necessary, except for the first one provided which goes at either the top or bottom of the stack (flavor text suggests bottom) without being turned or flipped. You will end up with the following stack:

```+-+-+##+-
#+-#-##-+
#-+#+-##-
-+-+-##-+
#####+-+-
#-+-#-###
-+-+###-+
+-+-+#-+-
##-+-##-+

-+-+-+##+
+-+-+##+-
#+-+-#+-+
##+###-#-
+#-#+-+##
-########
+-+-#+-+-
-+-##-+-+
+-+###-+-

+-+-+-##-
-+-+-+#-+
##+-+##+-
+##+-#+-+
-+####-+-
+-+-+#+-+
-+-######
#-##-+-+#
###-+-+-+

-+-+-+-##
#-+-+-+#-
##-+-+-#+
-#+-+##+-
+####-+-+
-+#+-+-+-
###-+-##+
-+-+##+##
+-+##+-+-

##+-+-+-+
+##+-+-+#
-+#-+-+##
+-#+####+
-+##-+#+-
+-+-+-+-#
-+-+-####
+-+###-+-
-+##+-+-+

+-#+-+-+-
-+#-####+
+-#+-+-+-
-+#######
+-+-+-+-+
-+-#-+#+-
+-#######
-+#-+-+-+
##-+-+-+-

-+-#+-+-+
+-+#-+-+-
-+-###+-+
+-+-+#-+-
#+-+-####
#-####-#+
-#+-+-+#-
+#-+-#-+#
##+-+#+-#

+-#+-#-+-
-+#-+#+-+
+##+-+-+-
-+####+-#
+-+##+-##
-+#-+-+#-
+-#+-+-#+
-+##+-+#-
##-+-+-##

-+-#+-+-+
+-+#-+-+-
-+-###+-+
+-+-+#-+-
-+-###+-+
+-+#-+###
-+-#+-#+-
+-##-+#-+
-+#-+-#+-```

Now, through each vertical stack of magnet-ends, add up the total field strength, considering the +s and -s and the strength printed on each frame. Use this value to Caesar-shift the letters printed on one grid. This gives the clue MAGNETIZABLE METAL PLACED IN A LATTICE THAT MIGHT BE AN EIGHT LETTER WORD MEANING FOOTBALL FIELD, which clues GRIDIRON.