18+ (eighteen plus), for prepared piano, was composed in 2017 at the initiative of the Slovenian Composers’ Society. In contrast to traditional or less conventional piano preparations—which explore various acoustic characteristics of the instrument—the piece 18+ approaches the piano sound in an entirely different way. The pianist places vibrating devices (vibrators), of the kind available in erotic toy stores, directly onto the piano strings. These vibrators, through their trembling, excite the strings; they may move on their own due to vibration, but the direction of their sonic surfaces is steered by the pianist using two percussion mallets.

The vibrators, differing in weight, power, and rhythmic vibration patterns, are gradually introduced into the piano, allowing the pianist to sculpt a wide array of sonic landscapes. This progression ultimately leads to a climax. The preparation in 18+ primarily involves shielding the gaps between the strings and the dampers, preventing the vibrators from falling onto the soundboard and producing uncontrolled resonance.

Both the technical and formal elements of the piece clearly allude to content typically restricted by state institutions to audiences over the age of 18—hence the title.