# project euler 60
# ? n
IsPrime ← memo(=1⧻°/×)
# [all pair-concatenations of [n]] ? [n]
Pairs ← ≡(⍜°⋕/◇⊂) ⧅≠2
# [all primes 1 through n] ? n
Primes ← +1⊚≡IsPrime+1⇡
# do numbers [n] form all prime Pairs?
# bool ? [n]
Check ← /↧≡IsPrime Pairs

⍤⤙≍ 1 Check [3 7 109 673]

⧅<4 Primes 1000
▽⊸≡Check