In this file there is a long object -- left and right.  There are a series of vertical shape and two vertical strokes crossing it.  I have to repeat the pattern that these vertical lines make.  I want the vertical lines to be shortened so they do not extend beyond the horizontal shape.  I cannot simply copy/paste because the horizontal object is so irregular.  I have tried clip/set and I cannot get it to cut the vertical lines so they do not extend beyond the horizontal shape. I have tried all the options under path/division etc.  I have worked on this for hours, I am asking out of desperation.  Note that the blue object is a shape and the 2 blue lines are strokes -- grouped (I can't seem to ungroup them).  I  have watch many youtube video  on each approach

So how so I trim the vertical lines so they do not extend beyond this particular horizontal shape? 

Thank you for your help.

Something like this ? 

Create a set of rectangle clones. Convert them to one path. 

Then clip it using a copy of the original path. 

Or do you want the tops of the rectangles to remain horizontal ? 

I have edited the tile of this topic to something more descriptive than "wits end". A topic title should indicate the nature of the contents.

This is a better way to do it. 

Create a series of bars using Edit>Clones>Create Tiled Clones.

Use Edit>Clones>Unlink Clones Recursively 

The Path>Combine Path on the bars created.

Then Path>Intersection on the combined bars and a copy of the shape path.

Then on the resulting paths Path>Break Apart. 

The select all bars and use Extensions>Render>Frame. Set the margins etc to zero.

This will frame the bounding box of each bar. 

I have attached the result.

Thanks for the time you spent responding to my request for help.  The responses seemed to concentrate on how to replicate the pattern.  Attached is a very simple example.  The vertical red line crosses the blue horizontal line.  I want to somehow in one action trim off the red above the line and the red below the line so that it looks like the object to the right.  Of course, I can just make the red object smaller and put it on top of the blue one.  However, in my design I need to achieve this many, many times. I have tried every path action and cannot get anyone to do this.  There must be a simple way to do this,

Your time for answering this simple question is appreciated.  I have spent hours trying to figure this out, googling, youtubing etc.

If you are going to carry out a path intersection as in the simple example you have posted.

You just need two overlapping paths. 

Then go to Path>Intersection.

The original paths will be destroyed, and the intersection will remain.

So before you do the intersection, select the horizontal path and use Edit>Duplicate

After selecting two paths, one horizontal and one vertical you will have remaining:

The resulting intersection path and a spare horizontal path.

You may have to change the colour of the intersection path at that point.

You can group them together if you want.

The method described by Inklinea in #4 is spot on... disregard making the bars using clones, if you already have the vertical bars.

Note:  the OP's vertical bars include some that are strokes... those will need to be converted to paths and broken-apart before combining with all the vertical bars.