Three or more Parallel lines

Three or more coplanar parallel lines 

This is a staircase that contains three or more parallel lines because the three lines never intersect. Stairs can be found inside and outside. Stairs are used in the real world to go up and down to different levels in buildings. This falls under marketing industry because this picture was advertising a house.

I found this picture online http://www.google.com/imgres?um=1&hl=en&biw=1186&bih=640&tbm=isch&tbnid=apDp1_Y2V04jPM:&imgrefurl=http://my-creativebook.blogspot.com/2012/01/stairs-strairs-stairs.html&docid=ZEBCmOkK8vI8IM&imgurl=https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIhU7CbrmNU5KQKJxtjJtzRDNncv6lgPHangK49N7SKrjwHWEy-EqQUvwfZOM-CvVWK8aVtnBAo0w_uQmhidYeE_wDGRypqkBAbOHoEJLeWoZQdwE4tbyBJCBFG3h4jgkOZptAy1rRywo/s1600/stairs-cool.jpg&w=450&h=598&ei=1b6JUJTwFOSE0QGryoGAAg&zoom=1&iact=hc&vpx=831&vpy=285&dur=154&hovh=259&hovw=195&tx=124&ty=188&sig=101161591993119626923&page=1&tbnh=137&tbnw=97&start=0&ndsp=20&ved=1t:429,r:12,s:0,i:171