Herring and egg sandwich tower

Spread slices of bread with butter and cut them into three- or quadrangular pieces. Put a piece of herring fillet or a series of thin pieces of herring on each piece. Sprinkle chopped spring onions on top and cover with a slice of hard-boiled egg. On the top sandwich, spoon a little thick sour cream and a few long slices of spring onion. Put three or four sandwiches stacked on top of each other with a stick.