Construction of Arbitrary Robust One-Qubit Operations Using Planar   Geometry
  We show how to construct an arbitrary robust one-qubit unitary operation with a control Hamiltonian of $A_x(t) \sigma_x + A_y(t) \sigma_y$, where $\sigma_i$ is a Pauli matrix and $A_i(t)$ is piecewise constant. Our method, based on planar geometry, admits a simple and intuitive interpretation. Furthermore, the total execution time and the number of elementary gates of the obtained sequence are comparable to those of the shortest known concatenated composite pulses. 
Tsubasa Ichikawa, Jefferson G. Filgueiras, Masamitsu Bando, Yasushi   Kondo, Mikio Nakahara and Dieter Suter
quant-ph