Take 3 slices of bread, Place the first slice of bread on a table. Spread with mayonnaise. Top with a layer of tomato slices and boiled eggs slices. Place another layer of bread and spread with mayonnaise. Top with a layer of avocado slices and add a few drops of lemon juice, salt and pepper. Cover with another slice of bread. You can make rectangles, triangles or any shape you want. Serve immediately or store covered with a wet cloth until ready to serve.