an eraser is a kind of solid
many_pencils has erasers one_type_of_eraser is rubber_erase. pencil_eraser is consumable_product. blackboard_eraser is eraser. ink_eraser is eraser. blackboard_eraser is device_officeproduct_nonconsumable. pencil_eraser is consumable_office_device. eraser is implement. pencil_eraser is flexible_thing. rubber_eraser is eraser.