This is a demo, previously proposed in the exibit Sperimentando 2014, that shows the capabilities of the Kinect sensor.
You stand in front of the Kinect where just below is placed a monitor. You can create virtual 3D solids by reaching with your hand to the edges of the screen to select the shape and color, then grip with both hands to give the solid its size.
A "remastered" version is presented to Sperimentando 2018.