Cube-2 is a prototype of building block scalable reconfigurable accelerator using an inductive coupling interconnect. It is consisting of a ultra low leakage embedded processor Geyser and coarse-grained reconfigurable accelerators CMA (Cool Mega Array). A Geyser chip and multiple CMA chips are stacked, and a powerful network is formed by using the inductive coupling interconnect. The performance can be enhanced by increasing the number of CMA chips. JPEG decoder is implemented with a cooperation of Geyser and CMAs, and low power execution by controlling the power supply voltage of CMAs is demonstrated.