I love this crochet pillow called the Catch A Wave Crochet Pillow. I love the size, simplicity and especially, the whimsical wave in this graphghan 'like' concept.
To help you further, I have completed a detailed tutorial for graphic work such as this. The tutorial has been designed to teach you about doing graphghans and pictorial work. There are 7 major steps in this type of concept, with micro lessons in each—everything from considerations of the design, planning, yarn techniques and more.
With this lovely yarn, you can make this project as your test ground and have an incredible home decor project.