I've been exploring easy card structures I can make using standard card blanks. Here's one where the card front is folded back forming two panels - one hidden on the inside - so that half of the inside shows through.
This is what it looks like when opened:
Card Base - Simply score a line dividing the card front in half vertically & fold as a mountain fold. The pre-scored line will be folded as a valley fold.
Panels - I cut paper from a HOTP Cardmakers Personal Shopper kit - so about 3/8" of the white base card shows all the way around. Rather than using paper to mat all of these, I drew a dark purple line around them using a ruler & one of my Zig Scroll & Brush Markers.
Border - narrow piece of paper from the kit. I drew a dark purple line on either side as for the panels, then matted with white & dark purple before adding it as you see here. Because of the way the card is constructed, this border is seen whether the card is open or closed.
Focal - The focal is a panel from the kit. I cut it with a narrow white border & then matted it on dark purple.
Butterfly Embellishment - from the kit - matted with white & then purple.