The long-winded method one which will allow you to only copy trapezoidal shapes.
To reduce art to standard shapes only
- Copy lines to new layer
- Hide visibility of old layer
- Select lines,
Object > Expand
- Draw rectangle of area you want to retain.
- Select lines and rectangle
- click Crop button on the Pathfinder Panel
- Draw a no-fill, no stroke, rectangle
- Choose
Select > Same > Fill & Stroke
- Hit the Delete key.
- Select the lines (which are now trapezoidal shapes)
- Copy
- Paste wherever you want.
- Possible Problem with this method is the lines are not easily edited now. So should you need to alter the angle, you'll have to repeat the steps above. Any non-proportional scaling will change all angles of the lines, including the ends. In addition, reuse of this artwork will increase overall file size.
A second method....
Mask the lines rather than editing them.
- Draw a rectangle on top of the lines for the area you want to retain.
- Select the lines and rectangle
- Choose
Object > Clipping Mask > Make
- Possible problems with this method is the need to edit clipping mask contents should you need to edit the internal lines. Not a huge hurdle, but depending upon the artwork, it can be time-consuming. In addition, reuse of this artwork will increase overall file size.
A third (preferred here) method....
Simply use a pattern and rotate the pattern.
- Create a straight horizontal or vertical line pattern by simply dragging a series of strokes or shapes to the Swatches Panel - Be certain to double-check the odd/even rules so the pattern repeats correctly.
- Fill any shape with the pattern
- Choose
Object > Transform > Rotate
and uncheck the "Transform Objects' option - which will check the "Transform Patterns" option - and then enter the amount of pattern rotation you desire. This results in angled pattern lines within the shape.
- Benefits to this method are pattern angles can be changed at any future point for reuse and ease of editing and non-proportional scaling of the pattern object will not result in angles being altered (or if the angles are altered, then can be reset with a click). And file size is not increased when the same pattern is applied to multiple objects (even if the pattern angles are different).