  We present the ptychography reconstruction of the x-ray beam formed by
nanofocusing lenses (NFLs) containing a number of phase singularities
(vortices) in the vicinity of the focal plane. As a test object Siemens star
pattern was used with the finest features of 50 nm for ptychography
measurements. The extended ptychography iterative engine (ePIE) algorithm was
applied to retrieve both complex illumination and object functions from the set
of diffraction patterns. The reconstruction revealed the focus size of
91.4$\pm$1.1 nm in horizontal and 70$\pm$0.3 nm in vertical direction at full
width at half maximum (FWHM). The complex probe function was propagated along
the optical axis of the beam revealing the evolution of the phase
singularities.
