Space trap construction, has top step whose front edge stretches parallel from peripheral edge part, common axis inclined in vertical plane common imaginary axis, and imaginary plane extending to another peripheral edge part

摘要

The construction has multiple intermediate steps (7-23) surrounding a common axis (41) and supported by a mutual support. A rear long edge, and inner and outer edges are located near a common center line. A common cover covers an imaginary center line circumference surface. A peripheral edge forms a projection on a base (25). A front edge of a top step (5) stretches parallel from a peripheral edge part. The common axis inclines in a vertical plane common imaginary axis. An imaginary plane extends near an inner end edge of the top step to another peripheral edge part (31).