These materials were developed partly through support of the National Science Foundation, (awards 1042210, 1535276, 1648684, and 1738598).Bootstrap:Physics by Bootstrap, AAPT and AMTA is licensed under a Creative Commons 4.0 Unported License. Based on a work at www.BootstrapWorld.org. Permissions beyond the scope of this license may be available by contacting schanzer@BootstrapWorld.org.