# project euler 39

S ← ⧻(
  ⊸(▽⊸(
      =/+⊃↙₂⊣°√ ⍉
    ) ⧅<3 +1⇡⌊÷2)
  ▽⤚(=/+ ⍉)
)

# same as S but filters in different order
S′ ← ⧻(
  ⊸(⧅<3 +1⇡⌊÷2)
  ▽⤚(=/+ ⍉)
  ▽⊸(=/+⊃↙₂⊣°√ ⍉)
)

⊢▽⊸(=⟜/↥wait≡poolS′) +1⇡1000

# ⊃($new ⊙◌⍜nowS′|$old ⊙◌⍜nowS) 840

# it seems S' is faster on bigger numbers (roughly), 
# and it pays off here, barely.