Particle distributions at different times in simulations without focusing (left column), with focusing (middle column), and with a free-escape boundary in the upstream at Z = αL, α = 1 (right column) for an oblique shock propagating outwards from the Sun along an exponentially decreasing magnetic field. The horizontal dotted lines give the injection momentum, and the dashed line in panel (h) gives a characteristic curve for an advecting downstream population undergoing adiabatic cooling. The horizontal stripes in the distributions result from the consecutive interactions of the initially mono-energetic particles with the shock.