Fear of flipping two very full cups on a 20x24 canvas with acrylic pour. 

The cups I use are made from vegetable materials and are fully compostable, they are slightly softer than regular plastic cups especially when they're full of paint, so I was somewhat concerned that the pressure needed to hold them onto the canvas would end up squashing them and bursting paint everywhere. My daughter took full advantage of my hesitation and grabbed the camera. At the end is a picture of the finished painting.