See https://en.wikipedia.org/wiki/Billion_lauHs_attack.
-- in.cue --
f: [g, g, g, g, g, g, g]                  @test(shareID=G, at=0) @test(shareID=G, at=3) @test(shareID=G, at=6)
g: [h, h, h, h, h, h, h] @test(shareID=G) @test(shareID=H, at=0) @test(shareID=H, at=3) @test(shareID=H, at=6)
h: [i, i, i, i, i, i, i] @test(shareID=H) @test(shareID=I, at=0) @test(shareID=I, at=3) @test(shareID=I, at=6)
i: [j, j, j, j, j, j, j] @test(shareID=I)
j: 1
-- out/eval/stats --
Leaks:  0
Freed:  34
Reused: 0
Allocs: 34
Retain: 0

Unifications: 34
Conjuncts:    34
Disjuncts:    0
-- out/todo.txt --
v2 expanded all shared references exponentially (7^4 = 2401 list elements for f,
resulting in ~3726 lines of output), while v3 uses structure sharing (~(g), ~(h),
~(i)) to represent the same value compactly (29 lines).
