An interactive projection of St. Ludmila paraphrases a fuel reaction in an engine. The two towers are conventionalized drums, which pistons during the firing reaction oscillate in a direction of the main shelf into the towers. The energy of firing spins the rosace. Elements of the fuel are represented by two letters (as in the chemistry) glow a light, by the movement they detect various parts of facade. Moldings and pillars, which enter into the forefront stay dark and the space effects becomes more visible. All the elements are made by the viewers itself, through a simple web interface. The viewer creates the element by filling in two letters- the initials , which are common to use in electronica navigation. This interactive projection has been made for a Signal festival.