Kadoodle Bug Designs a few years ago. I kept the front of the card simple, layering cardstock for the background and running the blue cardstock thru Stampin' Up's "Cloudy Day" embossing folder for the sky.
Just for fun I used egg and flower shaped panels in place of the rectangular panels typically seen with this style of pop up. Sentiments for the inside and front of the card were computer generated, using Bryce ttf.
Side view here shows the pivot mechanism which holds the accordion folded panels and creates the fun twist and pop up action of this style of card.
There are many video tutorials for this type of card on YouTube if you do a search for "Twist Panel Pop Up Card". I usually like to watch several different ones since everyone has different helpful tips and tricks to make the assembly of this card go smoothly.