In Shwetambar Jain tradition, different shapes of tilak / chandlo for men and women are usually a customary practice, not a core Jain scriptural rule.

Simple reason:

• Men and women are often marked differently by tradition and social custom.
• The purpose is usually recognition, decorum, and devotional tradition in a particular community or temple.
• In Jain Dharma, the main importance is inner purity, ahimsa, and devotion, not the outer shape of the mark.

Important point:

There is no universal Jain rule that says all Shwetambar men must use one shape and all women another shape. This can vary by region, temple, and local tradition.

Jain view:

Jain Dharma gives more importance to:

• bhava (inner भावना / intention)
• shuddhi (purity)
• vinay (respect)
• bhakti (devotion)

So the tilak is a symbol of reverence, while the real spiritual value is in conduct and भावना.

If you want, I can also explain the meaning of the different tilak shapes in Shwetambar tradition.