The symbiosis of music and architecture as a connection between their constituent parts is the basic theme of the interactive musical pavilion Arcousticon. It functions both as a real-time digital synthesizer and a physical shape visualizer. The main idea lies in presenting sound as a time changeable flow in space using tangible materials. The design process itself is a pure experimental one, trying to find interconnections between sound and form step by step. Whereas movement in architecture is usually a problem of its representation (metaphorical), Arcousticon establishes movement in a more literal form too. The pavilion, as a dynamic sound sculpture, interacts with the visitors movements in real time and responds by generating new spatial forms.