The movement of liquid down a vertical surface is a supposedly surautomatic method invented by Romanian surrealists Gherashim Luca and Dolfi Trost and described by them in Dialectique de Dialectique. As the name suggests it is an image made when liquid (e.g. ink)is poured or allowed to run down a vertical surface such as paper. The results are not supposed to be of aesthetic value and the method is calculated to be one of "scientific" image-making rather than, loosely speaking, artistic.