This is a 3D printed Valentine barcode medallion that relays the encoded message "I love you with all my heart" when the recipient scans it with their smart phone scanner.    I printed it 3" x 3" in PLA.     Create one process that prints the backplate in white PLA and a second process that prints the codes in black.    Set the stop height of process one to the height of the backplate and print it (white).    IMPORTANT:   You have to determine what that height is in your slicer particularly if you resize it before printing.   The printer will complete the white back plate.   Make sure you move the nozzle away from the work.   Heat the nozzle and change the filament to black.     Extrude until the black begins to extrude.    Make sure process 2 starts at the stop height of process 1 and run process 2.    Also make sure the bed heater is off for process two.