<R15> Modifications of parts. Parts may NOT be modified unless specifically listed as an exception in this rule. Examples of modifications include, but are not limited to, bending, cutting, sanding, gluing, or melting. The following exceptions are legal: Cutting metal VEX IQ or VEX V5 shafts to custom lengths. Bending parts which are intended to be flexible, such as string, rubber bands, or thin plastic sheets. Cutting VEX IQ pneumatic tubing to custom lengths.