Using a rectangle-shaped mold, FROMP resin containing 4a and G2 (4a:G2 = 5000:1) was initiated using a soldering iron on the top of the glass mold, and infrared thermography visualized the propagating front (Figure , Supplementary Video S4, S5). The polymerization process completed within 4 min for a 3 cm-long rectangle object, with a front speed of 6.3 mm/min. The low viscosity of the liquid monomer at room temperature allows the resin to be rapidly processed with various molds to efficiently obtain a wide variety of monolithic objects.