In this paper we describes a new concept of utilizing a mobile device or Personal Digital Assistant (PDA) for musical composition. We design a new interface that combines the ease of use of a pencil and the portability and customizability of mobile device. Our proposed kit involves the affordances provided by paper computing in order to provide user experiences to novice users. By effectively using the principle of electrical conductivity and signal processing, we have developed a functional prototype ("Birds on Paper") that enables users to compose their own music. Our proposed kit consists of 4 main elements, i.e.: pencil, birds-shaped sensor, hub connector, and mobile device or PDA. Pencil can be applied on a piece of paper as the main medium to visualize the musical composition. Touching the graphite surface of the drawing will trigger an audio feedback in the form of musical notes. Musical notes will be generated based on the thickness and the length of the pencil drawings, thus enables users to intuitively compose the music according to their preference. In addition to the description of the kit, we also discuss the concept behind the design and possible user scenarios.