Windfold, Mobile Bastion

At the beginning of your upkeep, sacrifice a land.
If you do, you get an experience counter. If you
don't, sacrifice Windfold, Mobile Bastion and you
lose half your experience counters rounded up.
Windfold, Mobile Bastion gets +1/+1 for each experience counter you have.
{t}: Add X mana in any combination of {g} and/or {w} where X is the number of experience counters
you have.