In this video I show a PID-controller (see https://en.wikipedia.org/wiki/Proportional%E2%80%93integral%E2%80%93derivative_controller for more details) build with my visual programming system codeflowcanvas.io ... the PID-controller example can be found on demo.codeflowcanvas.io. It uses expression nodes, global variables and flow-variables to handle the calculations and state. In a bar-chart the output of the mechanism can be seen. In this example the target value is 100 , and when moving the input value slider, that value is used as a measurement and the algorithm brings the measurement to the wanted value (100). This process is visualised in the bar-chart. When the speed of the flow is set to maximum (in the top left corner), the "program-counter"-animation is not shown and it runs as fast as it can in realtime. That helps for these kind of algorithms.