This makes for a very rigid, inflexible construction. Railroads also faced antiquated work rules and inflexible relationships with trade unions. This generally worked but was inflexible and inefficient. Aston suggests adjustments but Davies proves to be callous and inflexible. Despite the poetic title, his urban vision was authoritarian, inflexible and simplistic. The classic model of Constraint Satisfaction Problem defines a model of static, inflexible constraints. Duties were fixed by custom, inflexible and understandably resented by the workers involved. Captain Diebitsch was criticized for being a harsh and inflexible officer. Metal anklets are of two types&colon; "flexible" and "inflexible". Hunter characterized the small-market owners as being inflexible in negotiation. This had previously been impossible, as the first mask was made of inflexible metal. Zinc white dries slowly and creates a relatively inflexible paint film. However, a smooth solid highly conductive shield would be heavy, inflexible, and expensive. The religious frame in Tabari's account is therefore not inflexible or exclusive. He was completely inflexible on this requirement.