In Hinduism much importance is given to the symbols than most other religions. The Hindu symbols range from the mark one puts on the forehead to the idols of the deities that get worshipped by the ardent Hindu devotees. Each one has its own significance.
Hinduism at its core maintains that there is one God and many see It in different ways (Ekam sad viprAH bahuta vadanti). This God is Formless and is beyond the limitations of the comprehension. This is the basis on which many of the great sages meditate on this Supreme Being That is beyond any contours. So why are so many forms ? The God in Its natural form being very difficult to comprehend, leave alone loving that God and worshiping with devotion, the simple minds would certainly need a way through which they could worship the Boundless God in a fairly simplified manner. But at the same time it should not contradict the basis that the God is beyond forms in any way. Hinduism maintains that because of the abundant Grace of the God, It revealed Itself in the Holy symbols for the humans and other creatures to worship. These symbols are easy to comprehend for the minds of the normal human beings, but at the same time they are just symbols than objects themselves, which means that they symbolically indicate the God, Which is beyond the exploration of knowledge. Such symbols are the praNava (aum) which is held in high esteem by all sects of Hindus and the glorious shiva lingam (1) (meaning symbol of Shiva, the God) that is considered the most sacred symbol of worship for the Shaivites. The intention is that the Formless Supreme could be achieved by simpler means of these formless-forms - the symbols.
In a way these Hindu symbols are abstract representation of the God. These are quite closer to the ideal as they form a bridge between the Formless one and the mind that expects a form. The simpler minds benefit better if the God could be correlated with the day to day lives they interact with. The God certainly is Graceful to the upliftment of the creatures, It took various forms in various occasions blessing either in valorous or joyful or yogic postures. There are numerous of these forms that Hindus worship in their temples, which are built in a gigantic manner with the patronage of various emperors that stand as the glorious homes of art and architecture. The mAhEshvara mUrthams (2) are good examples of such forms of God.
In fact the Hindus wear various marks on their forehead that also have spiritual significance. For example the ash that the Shaivites wear represents the ash that the Supreme Flame - Lord Shiva has smeared on Him always. The same way the shrIchUrNa and the tilak have their significance and indications. In essence Hindus achieve the Supreme Things, by simple ways following the symbols.
Oh God, Your Feet is beyond the worlds beneath
and Your Crown beyond the universes above !
You are Immeasurable, Unexplorable, Unimaginable !
But how simple You have come as a shivalinga in my hand !!
Visit the Shaivism Art Gallery for pictures of hindu gods/saints.