I purposely gave you dimensions that are somewhat uneven. A quilt, 39" x 64" with a 3" border, changes the top to 45" x 70" . Start with drawing a diagram with your own dimensions.

On your diagram, draw the corner lines on all 4 corners. We'll ignore the corners for now so the dimensions we are dealing with are 3"x 39" for the top measurement. To get the repeats, I use machine adding tape to get the width of the repeats. Working on the top and bottom measurements, I cut a strip of adding tape 39". If I fold it in half, I can get a repeat that is 18½" wide. If you want a vine, take this measurement of 18½" width and adding the 3" height, transfer it to a piece of freezer paper or paper large enough to accomodate the measurements.

Fold in quarters horizontally as shown.
Fold again vertically.

Draw your vine as shown in red.

Repeat with the sides. Now you may find that folding it in halves is not appealing to you. You can try folding your adding tape in thirds and see if it looks better. Just draw the new repeat dimensions but keep the other folds as above. You are now left with the corners. Cut a square 3" x 3" (in this case the width of your border).

Transfer the previous markings to the corner and draw an arc. This will connect your vine.

Making a diamond repeat is done the same way. Fold your paper in quarters to your dimensions. I've tried to show you how to proceed by using different colors.