  We experimentally demonstrate a simple scheme for generating a four-photon
entangled cluster state with fidelity over 0.860 $\pm$ 0.015. We show that the
fidelity is high enough to guarantee that the produced state is distinguished
from Greenberger-Horne-Zeilinger, W, and Dicke types of genuine four-qubit
entanglement. We also demonstrate basic operations of one-way quantum computing
using the produced state and show that the output state fidelities surpass
classical bounds, which indicates that the entanglement in the produced state
essentially contributes to the quantum operation.
