Even the offerings are educationally significant. A glass of water symbolizes the Dharma. The water is clean symbolizing that our minds need to be as pure as the water. It is calm without a single ripple, symbolizing the tranquility in our hearts. Thus, to have purity and equality of mind.
Flowers symbolize the Six Paramitas.
Fruits are not offered to the Buddha or Bodhisattvas to eat. They are to remind us that if we want to get the sweet fruit or the good result, we must cultivate and accumulate good deeds or the cause. Thus, everything we see in the way place is a teaching aid. The Buddhas and Bodhisattvas neither smell nor eat, they want for nothing. You will not see anything in the cultivation and lecture halls that does not symbolize some teaching.