Before going into glyph recognition, there is another task which needs to be solved first - find potential glyphs in an image to recognize. The aim of the task is to find all quadrilateral areas which may look like a glyph - an area which is promising enough for further analysis and recognition. In other words, we need to find 4 corners of each glyph in the source image. It so happened that this task is the hardest one from the entire glyph searching-recognition project.