Ghave, which enters the battlefield with five +1/+1 counters on it.
Activate
Ghave's first ability by paying ({1} magic symbol) and removing a +1/+1 counter from it, creating a 1/1 Saproling creature token.
Activate
Ashnod's Altar by sacrificing the Saproling, adding ({C} magic symbol) ({C} magic symbol) .
Repeat from step 2 three additional times.
Repeat from step 1.
Notes
If you have removable +1/+1 counters on creatures you control, you may start by doing steps 2 and 3 until you either have no more removable counters or have at least ({4} magic symbol) available, and then proceed from step 1. This can reduce the starting mana of the combo.