Saheeli, the Sun's Brilliance | Mana Echoes | Gemstone Array

(and one other card)

Saheeli does not have summoning sickness.
({U} magic symbol) ({R} magic symbol) available, plus an additional ({U} magic symbol) ({R} magic symbol) if you control less than three creatures that share a creature type with
Bounding Krasis.

Activate
Saheeli by paying ({U} magic symbol) ({R} magic symbol) and tapping it, creating a token copy of
Bounding Krasis with haste.
When the token
Bounding Krasis enters the battlefield, it and
Mana Echoes trigger.
Resolve the
Bounding Krasis trigger, untapping
Saheeli.
Holding priority, if you control less than four creatures that share a creature type with
Bounding Krasis, repeat steps 1 through 3 one additional time.
Resolve all
Mana Echoes triggers, adding ({C} magic symbol) for each creature you control that shares a creature type with
Bounding Krasis for each trigger resolved this way.
Activate
Gemstone Array twice by paying ({4} magic symbol) , putting two charge counters on it.
Activate
Gemstone Array's second ability twice by removing two charge counters from it, adding ({U} magic symbol) ({R} magic symbol) .
Repeat.