In the photo, the green straight rods and the red curved ones are from Bornimago, while the plastic panels are from the “Castle” construction set. The construction set pieces combine well with the magnetic rods from Bornimago, except for the plastic half-circle pieces (a separate blue piece in the photo). To fit this piece, you need the original curved rods from the “Castle” construction set: they are either slightly shorter or slightly thinner than the Bornimago ones (I haven’t figured it out yet), but the piece made with the original “Castle” rods doesn’t fall off.
