Read the letter on the ground. Take note of the last line of the poem. Those are the answers to the riddle.
After you read the letter, place the Pocket Mirror on each of the lights. Every time you get an answer right, remove the pocket mirror from the light and place the shard in it. You want them to intersect and create a point down the middle.
RED ANSWER - Rage
BLUE ANSWER - Grief
RED faces RIGTH
BLUE faces LEFT