Fisher Transformation by Mr Snaky

Puzzle explanation

The corrections to misprints in clues spelt out “Alexandrian maths icon”, referring to Heron of Alexandria, who devised a formula to calculate the area of a triangle from the lengths of its sides. Heron’s formula is A = √(s(s − a)(s − b)(s − c)), where a, b, c are the side lengths and s = (a + b + c)/2. After enciphering, the grid’s perimeter entries were HERONIAN, TRIANGLE, SQUARE LEGS, PYTHAGORAS, ULTIMATE, QUESTION. A Heronian triangle is one with sides of integral length. In this case, one side was (as specified in the preamble) the grid’s diagonal of length 20 cells (the hypotenuse of a 12-16-20 right triangle) and the others were a 7-cell length across the top of the grid and a line connecting them of length 15 (the hypotenuse of a 9-12-15 right triangle). For the formula, s = (20 + 7 + 15)/2 = 21 and the area A = √(21(21 − 20)(21 − 7)(21 − 15)) = 42 (coincidentally also the length of the triangle’s perimeter). Cell 42 was therefore highlighted, also being the answer to “the Ultimate Question of Life, the Universe, and Everything” in The Hitchhiker’s Guide to the Galaxy. The puzzle’s title was a reference to the fish diet of herons.

Clue explanations

Conventions: * = anagram, < = reversal

No Misprint Answer (letters omitted in grid) Explanation
Across
1   ULTIMATE U(sefu)L + TIME around AT
7   STEAM IR(O)N MATE’S * + IRON
13   CLUES CUES around L
15 b(A)nd CRAPE CE around RAP
18   (T)ALAK TALK around A
20   PINDAR PINDAR(i)
21 bu(L)ly HECTORER HE + C + TORE + R
22 G(E)tting ACQUIST ACQUIT around S
24   CONCERN ONCE in CR + N
25   ISH(BEL) (l)IBEL around SH
26 fi(X) ANNEX AN + NEX(t)
27 gr(A)ss GOUTFLY (OFT UGLY) *
30   ME(R)EL EM < + REL
31 (N)o SCULLE S + CULL + E
33   OSSI(S) OS + SIS
35   A(G)AST (T + SAGA) <
36 (D)igress ERRANT ERRAN(d) + T(iger)
38   (A)RCOS (SO + CRA(g)) <
39 w(R)iting AMORISM A + MOR + IS + M
41 st(I)ck JERID JER(k) + ID
42   A(W)DL AWL around D
44   (F)AN-SHELL FAN’S + HELL
48 M(A)llard PLUMULA PLUM + U + LA
49 can(N)ed GLORIOUS GLO(w) + IOUS after R
50   GALENI(C) (GAELIC + N) *
52   CE(C)AL EC in CAL
53 wigwa(M) OSAGE O + SAGE
54   (U)RANIC (INCUR A) *
55   ER(EW)HONIAN (WAN HEROINE) *
56   PLANCHET PLAN C + THE *
Down
2   ALIAS ALI + AS
3   MUNCHES HUNCHES with M for H
4   LE(N)D L + END
5   ECR(U) ((colo)UR CE(nturies)) <
6   IRISES I + RISES
8   MECC(AN)O COME * around CAN
9   (L)ENTO O(vate) after LENT
10   TAR(O)C CARTO(mancy) *
11   SLEE ELSE *
12   R(EM)ARRY RE + MAR + R(iot) + Y
13   CAMP-CHAIRS CAMP + CH + AIRS
14 w(A)nder SAUNTERERS (ART ENSURES) *
16 (T)oy PEN-GUN PENGUIN − I
17 c(H)ew MONTELIMAR MO + TRAMLINE *
19   MISLUCKING MUCKING around ISL
23 (S)een INDRI IND + RI
26 p(I)tched ALTO ALT + O
28 ro(C)k ULURU LU in URU
29 r(O)ad FORD F + OR + (goo)D
32 do(N)s CAMPUS CAMP + US
34   SCALENE SCALE around EN
37   TELEG(RAP)H TELE + GRAPH
39   (B)ANGER ANGER after B
40   S(A)LOON (A + LOO) in SN
43   DANI(E)L DAN + IE + L
45   SLA(I)N S(o)L(v)A(t)I(o)N
46   HOLE homophone of WHOLE
47   LIPI(D) ID after LIP
50   GEA(L) GEL around A
51   LA(R)N LAR + N
Back to 2026 menu