This makes for a very rigid, inflexible construction. Defects differ between flexible and rigid pavements. Their rear legs are fairly rigid and sturdy. Engineers develop packages from a wide variety of rigid and flexible materials. Pellicles of protozoan organisms vary from flexible and elastic to fairly rigid. Solids have more rigid and fixed structure than liquids. Its properties are usually categorized based on rigid and flexible PVCs. The starting blocks consist of two adjustable footplates attached to a rigid frame. Their flatness is achieved by stretching them on a rigid frame. Historical navies were far more rigid in structure. Keratometry is especially important in the fitting of rigid lenses. The statues depicted him as massive, monolithic, rigid and unambiguous. Rotational inertia is often considered in relation to the a rigid body. Laws are regarded as social contracts rather than rigid edicts. Metalworking lathes evolved into heavier machines with thicker, more rigid parts.