Despite having several two-tier bento boxes, I actually find myself using a single layer box more often. I like the feel of all that open space to lay out the food, like for today's sunflower bento. You don't need any fancy accessories for this bento, and apart from laying out the fillings, it is pretty easy to make.
I made the sunflower using beef soboro (minced beef) and cut-up tamagoyaki (Japanese rolled omelette) - see how to make tamagoyaki for a pictorial step-by-step guide. The background is made out of cherry tomatoes and blanched snow peas on a bed of rice. I also added some stir-fried capsicum (hidden under the rice) for added flavour.
Directions for the sunflower petals:
Make a rectangular shaped tamagoyaki and slice it into 1/4 inch (or 1/2 cm) pieces as shown in the picture. Cut each rectangular slice into half diagonally to make one petal. Arrange in a circle to form the sunflower.