Melon Machine: Mystery Game ~20

Level 1:
1 lumber → → 1 lumber
1 lumber → → 1 lumber
1 lumber → → 1 lumber

Level 2:
1 lumber → → ERROR
1 lumber → → No Output
1 lumber → → 1 lumber

Level 3:
1 lumber → → 2 planks
2 planks → → 1 lumber

Level 3.5:
1 lumber → → 4 rods
1 lumber → → 8 rods (1/2 size)
2 lumber → → 1 lumber (x2 size)

Make a machine using level 3/3.5 correctly to unlock level 4!
Feel free to also just make machines, for either discovering the output (if none is provided) or seeing if your machine gives the correct result.

Preview:

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