8815
Four different designs were printed : two bending-dominant Kelvin cell structures , a stretching-dominant octet structure , and a mixture of the two with geometries chosen for equivalent stiffness .
 engineering feature: designs; application: cell; concept or principle: octet structure; concept or principle: geometries; machanical property: stiffness
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
 Entities: designs, cell, octet structure, geometries, stiffness 
Answer:
 engineering feature: designs; application: cell; concept or principle: octet structure; concept or principle: geometries; machanical property: stiffness