New pattern

After the brief conversation between Robin and Zara, she ran to find Billy to tell him the new orders.

While Robin rushed back to his room again to finish what he has to do...

The heat generation pattern may have finally taken shape, but the job of operating the furnaces is still far from over... what is finished was just a single part of the final picture.

For example, the heat generation pattern is available now and Zara will begin to practice drawing it on papers and hides of different attribute beasts with ordinary ink to raise her success rate and do not mess up when she draws it on the furnaces

but when the moment of actual execution comes, how would she draw it on the fire stones? What she will be drawing it with? what would be used to activate the pattern? And how is the pattern will be hidden after it is finished to prevent the spies from seeing it?