Sunlight passing through a window opening creates a distinct window-shaped block of light inside a room. why does diffraction not cause the window-shaped light to spread out?

Because it is shining in one place and the light isn't moving so the light will shine at one spot.

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.