Today, to symbolise the people of God gathered together round the table. A Nave Alter is used in the church. The colour of its decorations, reflect and and change over the liturgical year: 

Gold is used at major celebrations like Christmas and Easter.

Purple is used at the time of Advent in preparation fro Christmas.

Red is used for Pentecost and Palm Sunday, and in the Season of the Kingdom reminding us of fire and blood.

No cover is used in Lent, as a reminder of simplicity and penetence.

Green is used in ordinary time when no other colour is assigned.