The Baal Shem Tov loved light.
When candles were scarce, he instructed his disciples to collect icicles from the branches, place them in candleholders and light them.

The third Lubavitcher Rebbe said,
"For the Baal Shem Tov's Chassidim, ice burned and yielded light.
Today you sit in heated and well lit rooms, and yet it's cold and dark."