The Ardennes forest had very unpredictable weather and there were parts where it was raining and the track was wet, and other parts where the sun was shining and the track was completely dry
वितळलेल्या काचेत मॉलिब्डेनम मिसळल्यावर काचेचा रंग सूर्यप्रकाशात निळा होतो आणि रात्री तीच काच पूर्णपणे पारदर्शी होते.