Utilize the input text as a context reference, choose the right relationship between Stratasys and 3D printing from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

The 3D printing pioneers Stratasys Ltd. ( SSYS ) and 3D Systems Corp. ( DDD ) touched highs of $120.36 and $80.13 in 2014 and 2013 respectively.

Answer: industry