Ten real mechanical integration instruments shown with verified Wikimedia Commons photographs: Amsler and Coradi planimeters, rolling and polar models, integrators, and the NASA differential analyzer. Photograph credits: 1. File:Planimeter Full.jpg; Twdragon; CC BY-SA 3.0; https://creativecommons.org/licenses/by-sa/3.0; https://commons.wikimedia.org/wiki/File:Planimeter_Full.jpg; 2. File:Rolling Disc Planimeter (30764633442).jpg; Central Intelligence Agency from Washington, D.C.; Public domain; ; https://commons.wikimedia.org/wiki/File:Rolling_Disc_Planimeter_(30764633442).jpg; 3. File:Compensating Polar Planimeter (30880918765).jpg; Central Intelligence Agency from Washington, D.C.; Public domain; ; https://commons.wikimedia.org/wiki/File:Compensating_Polar_Planimeter_(30880918765).jpg; 4. File:Statens Kartverk Hønefoss - Polarplanimeter, Jacob Amsler (1854) (kartmuseet).jpg; Ssu; CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0; https://commons.wikimedia.org/wiki/File:Statens_Kartverk_H%C3%B8nefoss_-_Polarplanimeter,_Jacob_Amsler_(1854)_(kartmuseet).jpg; 5. File:Planimeter-CNAM 9513-IMG 5070-black.jpg; Rama; CC BY-SA 3.0 fr; https://creativecommons.org/licenses/by-sa/3.0/fr/deed.en; https://commons.wikimedia.org/wiki/File:Planimeter-CNAM_9513-IMG_5070-black.jpg; 6. File:Планиметр G Coradi Zurich.jpg; Vitaliy VK; CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0; https://commons.wikimedia.org/wiki/File:%D0%9F%D0%BB%D0%B0%D0%BD%D0%B8%D0%BC%D0%B5%D1%82%D1%80_G_Coradi_Zurich.jpg; 7. File:Planimetro rullo Coradi, Zurich, 1875 - 1925 - Caserta, Museo Michelangelo.jpg; MuMiCaserta; CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0; https://commons.wikimedia.org/wiki/File:Planimetro_rullo_Coradi,_Zurich,_1875_-_1925_-_Caserta,_Museo_Michelangelo.jpg; 8. File:Mechanical integrator CHM.agr.jpg; ArnoldReinhold; CC BY 4.0; https://creativecommons.org/licenses/by/4.0; https://commons.wikimedia.org/wiki/File:Mechanical_integrator_CHM.agr.jpg; 9. File:CHM Artifacts Amsler Integrator Model 4282 (3126342999).jpg; Marcin Wichary from San Francisco, Calif.; CC BY 2.0; https://creativecommons.org/licenses/by/2.0; https://commons.wikimedia.org/wiki/File:CHM_Artifacts_Amsler_Integrator_Model_4282_(3126342999).jpg; 10. File:Nordsieck Differential Analyzer at CHM.jpg; Tomwsulcer; CC0; http://creativecommons.org/publicdomain/zero/1.0/deed.en; https://commons.wikimedia.org/wiki/File:Nordsieck_Differential_Analyzer_at_CHM.jpg;