MX flat is an apartment for young couple, the basic principles which we used at design of this space, it flexibility and transformability in combination with laconicism and simplicity. The transformability was necessary for creation of a set of different scenarios of use of space. We used the modular system of sofas and have hidden an additional sleeping place in a living room, having combined it with a small workplace. Creation of a simple, functional and at the same time expressive interior was our purpose. We have got rid of all unnecessary walls to create open and free space. The principle of permeable space supports the aquarium which is built in a wall between a living room and bedroom, playing a "window" role between these two rooms. The light tone of walls in combination with natural materials create a complete image of a moderate and laconic interior which serves as an excellent background for the bright inhabitants.