(Note from the webmaster: Since Bob wrote this document, it has now been confirmed that Deceitful is indeed the correct hidden word. Nevertheless, this document still makes for interesting reading.)
I had thought that the solution to the XOR competition anagram was DECEITFUL but back in 1987 I submitted this to Logotron and received absolutely nothing back from them. I had not given this much thought in the intervening (22!) years until I saw Paul Collins's write-up. Back in 1987 I didn't have a computerised anagram solver but now modern science allows me to search for 9 letter and longer words containing the letters DECEITFUL on the assumption that the extra symbols (??!) perhaps represented extra letters. This gave me the following (with extra letters underlined) ...
UNINFLECTED seems to fit the bill (if we take into account Pauls observation of 'why should there be two distinct symbols for three distinct letters'). But this doesn't seem to have the same relevance as MULTIFACETED. My personal favourite from the list is COMPUTERFRIENDLY.
Paul states that the 15 symbols from a non BBC Micro version are L*UF*T?I*EC*E*D. The BBC Micro gave me L?UF?T!IECED. Comparing these gives the following table:
I would have expected the non-BBC version to have E for level 9 and * for level 10 to give some compatibility although why one has * and the other ? for the extra symbols is still a bit of a mystery.
A further thought was perhaps the extra symbols were spaces in a three word solution (although this would not work for the non-BBC version). My trusty anagram solver gave the following words made from DECEITFUL.
DECEITFUL CLEFTED DEFLECT DUCTILE FILETED LEUCITE CEILED DECEIT DECILE DEFECT DEFILE DELICT DELTIC DILUTE DULCET ELUTED FELTED FLITED FLUTED FUELED FUTILE LIFTED LUETIC TELEDU CITED CLEFT CLIFT CLUED CULET CULTI CUTIE DEICE DELFT DEUCE EDICT EDILE EDUCE EDUCT ELECT ELIDE ELITE ELUDE ELUTE ETUDE FELID FETED FETID FEUED FIELD FILED FILET FLEET FLIED FLITE FLUED FLUID FLUTE LUCID LUDIC LUTED TELIC TILDE TILED UTILE CEDE CEDI CEIL CELT CETE CITE CLEF CLUE CUED CUIF CULT CUTE DEET DEFI DEFT DEIL DELE DELF DELI DICE DIEL DIET DITE DUCE DUCI DUCT DUEL DUET DUIT EDIT EIDE ETIC ETUI FEED FEEL FEET FELT FETE FEUD FICE FILE FLED FLEE FLIC FLIT FLUE FUCI FUEL ICED IDLE LEET LEFT LEUD LICE LIED LIEF LIEU LIFE LIFT LITE LITU LUCE LUDE LUTE TEED TEEL TELE TIDE TIED TILE TULE CEE CEL CUD CUE CUT DEE DEL DIE DIT DUE DUI ECU EEL EFT ELD ELF FED FEE FET FEU FID FIE FIL FIT FLU FUD ICE LED LEE LEI LET LEU LID LIE LIT TED TEE TEL TIC TIE TIL TUI DE EF EL ET IF IT LI TI UT
Which leads to (for example) "I'd cue left" and many others.