Figure 2. Containers 2, 4 and 6. Length in cm. These containers were identical with the exception of the lengths of X and Y. Container 2: X=45 cm, Y=27 cm, container 4: X=47 cm, Y=25 cm and container 6: X=46 cm, Y=26 cm. The thickness and the materials of the walls,the lid and the underside, and the diameters of the vents were the same as for container 1 shown in Figure 1. The bottom area is rectangular with the inner measurements of 90*55 cm.