(a) Simple horizontal:

ABCDEF FEDCBA STUVWX XWVUTS
GHIJKL LKJIHG MNOPQR RQPONM
MNOPQR RQPONM GHIJKL LKJIHG
STUVWX XWVUTS ABCDEF FEDCBA

(b) Simple vertical:

AEIMQU DHLPTX UQMIEA XTPLHD
BFJNRV CGKOSW VRNJFB WSOKGC
CGKOSW BFJNRV WSOKGC VRNJFB
DHLPTX AEIMQU XTPLHD UQMIEA

(c) Alternate horizontal:

ABCDEF FEDCBA XWVUTS STUVWX
LKJIHG GHIJKL MNOPQR RQPONM
MNOPQR RQPONM LKJIHG GHIJKL
XWVUTS STUVWX ABCDEF FEDCBA

(d) Alternate vertical:

AHIPQX DELMTU XQPIHA UTMLED
BGJORW CFKNSV WROJGB VSNKFC
CFKNSV BGJORW VSNKFC WROJGB
DELMTU AHIPQX UTMLED XQPIHA

(e) Simple diagonal:

ABDGKO GKOSVX OKGDBA XVSOKG
CEHLPS DHLPTW SPLHEC WTPLHD
FIMQTV BEIMQU VTQMIF UQMIEB
JNRUWX ACFJNR XWURNJ RNJFCA

ACFJNR JNRUWX RNJFCA XWURNJ
BEIMQU FIMQTV UQMIEB VTQMIF
DHLPTW CEHLPS WTPLHD SPLHEC
GKOSVX ABDGKO XVSOKG OKGDBA

(f) Alternate diagonal:

ABFGNO GNOUVX ONGFBA XVUONG
CEHMPU FHMPTW UPMHEC WTPMHF
DILQTV BEILQS VTQLID SQLIEB
JKRSWX ACDJKR XWSRKJ RKJDCA

ACDJKR JKRSWX RKJDCA XWSRKJ
BEILQS DILQTV SQLIEB VTQLID
FHMPTW CEHMPU WTPMHF UPMHEC
GNOUVX ABFGNO XVUONG ONGFBA

(g) Spiral, clockwise:

ABCDEF LMNOPA IJKLMN DEFGHI
PQRSTG KVWXQB HUVWXO CRSTUJ
OXWVUH JUTSRC GTSRQP BQXWVK
NMLKJI IHGFED FEDCBA APONML

(h) Spiral, counterclockwise:

APONML NMLKJI IHGFED FEDCBA
BQXWVK OXWVUH JUTSRC GTSRQP
CRSTUJ PQRSTG KVWXQB HUVWXO
DEFGHI ABCDEF LMNOPA IJKLMN