Solution to Squared Key

by Julian West

The grid is a wordsearch, and contains the following thematic words.

Reading W<-->E:
EIGHTH NOTE, CHAINS, JUNO, PLUTO, COMET, RAIN, FLOWER, SEXTILE, PICK, NEUTER, PISCES, FLEUR-DE-LIS, ALEMBIC, ANCHOR, HOT SPRINGS, SHAMROCK, EARTH, YIN YANG, WHITE FLAG, SATURN, HOT BEVERAGE

Reading N<-->S:
NO ENTRY, CERES, ADI SHAKTI, LIBRA, FERRY, ARIES, COFFIN, WARNING SIGN, CHIRON, CHURCH, BALLOT BOX, CLOUD

Reading NW<-->SE:
GEAR, SUN, CHI RHO

Reading SW<-->NE:
CASTLE, SKIER, ANKH

In convential word-search fashion, the letters not involved in any of these words spell a message: SORRY BUDDY BUT THIS PUZZLE HAS YET A SUBTLETY.

To complete the puzzle, solvers must identify the theme which unites the words in the grid. They are all symbols in the Unicode block called "Miscellaneous Symbols" (2600–26FF). Each symbol therefore encodes to a pair of hexadecimal numbers according to its Unicode encryption.

These can be read as (row,column) indices into the grid, labelling the rows and columns from 0-15.

CLOUD		01 T
COMET		04 H
SUN		09 E
BALLOT BOX	10 S 
HOT BEVERAGE	15 O 
SHAMROCK	18 L 
ANKH		25 U
CHI RHO		27 T
ADI SHAKTI	2C I
YIN YANG	2F O
EARTH		41 N
SATURN		44 T
PLUTO		47 O
ARIES		48 T
LIBRA		4E H
PISCES		53 I
HOT SPRINGS	68 S
EIGHTH NOTE	6A P
WHITE FLAG	90 U
ANCHOR		93 Z
ALEMBIC		97 Z
FLOWER		98 L
GEAR		99 E
FLEUR-DE-LIS	9C I
WARNING SIGN	A0 S 
COFFIN		B0 C
NEUTER		B2 H
CERES		B3 A
JUNO		B5 R
CHIRON		B7 C
SEXTILE		B9 O
RAIN		C6 A
PICK		CF L
CHAINS		D3 B
NO ENTRY	D4 U
CHURCH		EA R 
CASTLE		EB N
FERRY		F4 E
SKIER		F7 R

This reads off as:
THE SOLUTION TO THIS PUZZLE IS CHARCOAL BURNER.