Cryptic Trilobite has at least two +1/+1 counters on it.
You control at least one basic Forest and/or Island.
({1} magic symbol) available.
Steps
Activate a basic Forest or Island by tapping it, adding ({GU} magic symbol) .
Activate Earthcraft by tapping Gilder Bairn, untapping the basic Forest or Island.
Activate the Forest or Island by tapping it, adding ({GU} magic symbol) .
Activate Gilder Bairn by paying ({2} magic symbol) ({GU} magic symbol) and untapping it, doubling each counter on Cryptic Trilobite.
Activate Cryptic Trilobite's first ability by removing a +1/+1 counter from it, adding ({C} magic symbol) ({C} magic symbol) that can only be spent to activate abilities.
Repeat from step 2.
Once you have infinite +1/+1 counters on Cryptic Trilobite, you may instead double the counters on any other permanent(s).
Results
Infinite +1/+1 counters on Cryptic Trilobite.
Infinite colorless mana that can only be spent to activate abilities.