Activate Ghave's first ability by paying ({1} magic symbol) and removing a +1/+1 counter from a creature you control, creating a 1/1 Saproling creature token.
Activate Ashnod's Altar by sacrificing the Saproling, adding ({C} magic symbol) ({C} magic symbol) .
Mazirek triggers, putting a +1/+1 counter on each creature you control.
Repeat.
Once you have infinite mana and +1/+1 counters, you may stop sacrificing the Saprolings to get infinite creature tokens.