Possible Clues:

• Partially seen from behind, sculptor I mistook for painter
• Painter of optical illusions offering nothing for a long time
• "Horse, Pipe and Red Flower" painter
• Picasso pal
• Artist with a museum in Barcelona
• Artist from Barcelona
• Joan __, Catalan painter and sculptor
• Barcelona's Fundació Joan __
• Joan ____, Spanish surrealist painter
• 'The Farm' painter Joan