What was Picasso 's most mysterious and challenging painting and when was it created ?
Here he paints with a precise , realistic style , based on studies of Dutch and Spanish masters , but with a subject that dissolves the boundaries between organic and mechanical and is more akin to the nightmarish scenes of the Netherlandish painter Hieronymus Bosch , whose " Garden of Earthly Delights " provided the model for the central , sleeping figure of Dalí 's work .