From the original:

“I dissolved some pure lidocaine and gentisic acid in 98% denatured ethanol. Then I put a small amount of the solution on a microscope slide in a thin layer. When the alcohol evaporated, the two compounds crystallize on the slide in a super thin layer. The slide is then placed under the microscope and illuminated with polarized light (plus a retarder/lambda plate). This particular image is a stitch of about 5*5 pictures taken with my iPhone mounted on the microscope with a LabCam adapter.”