Unlocking this requires a little research, but it's worth it. You can speed up the Infusion process or make the process cheaper. The downside of making this process faster means it would increase the cost of Infusion. The reverse goes with making the Infusion process cheaper (will make it much slower). The Infusion Speed Stone or Infusion Cost stone must be placed below each Pillar of the Altar:
You do not have to worry about symmetry when placing these down.