Synchronized fabrication of a hierarchical vascular structure with interconnected microchannels. A 3D printed PPC (1% PAG, UV irradiated) template is incubated inside DCPD resin (a0 = 0.25). FP is triggered from the left-hand side with a linear heat source and the template depolymerizes concurrently during the propagation of FP. A neat thermoset with interconnected microchannels resembling the primary and secondary veins of an Impatiens leaf is fabricated in 80 seconds. The video is presented at 3x speed. The scale bar is 5 mm.