'Test model (N2) for network ray tracing.' 0 1 1 / -20 20 -20 20 -20 0 / 0 surfaces 1 simple block: / 1 complex block: 1 / 'END of surfaces' / 'COMPLEX BLOCK' 1 'VP ' 1 1 2 3 0 / 6 6 2 -20 -15 -5 5 15 20 -20 -15 -5 5 15 20 0 -20 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 5.5 5.5 5.5 5.5 5.5 5.5 5.5 6.0 5.0 6.0 5.0 5.5 5.5 5.0 6.0 5.0 6.0 5.5 5.5 6.0 5.0 6.0 5.0 5.5 5.5 5.0 6.0 5.0 6.0 5.5 5.5 5.5 5.5 5.5 5.5 5.5 'END of complex blocks, end of the input data for the model' / ========================================================================