For better understanding of far-field diffraction patterns obtained in coherent X-ray diffraction I wrote a simple stand-alone application for laptops with built-in web cams. It allows to see coherent effects from different systems, which can be simply exposed to the web camera being drawn on the paper. There is a number of similar applications published, however in this case the application need no installation or additional modules. Additionally, Gaussian shape field of view is introduced for the input stream in order to satisfy oversampling conditions.