Steps
1)  Dissolve sugar by hot water
2)  Mix water chestnut flour, corn flour into a plain square container
3)  Add in evaporated milk and coconut milk, then mix them well
4)  Pour in the boiling sugar water, stir well until form paste
5)  Add in red bean, stir again until red bean in well distribution
6)  Chilled by refrigerator while paste is cooled down
7)  Cut into small square pieces, dish up and serve           
　

Remark 
If paste is too thin (not concentrated), boil it in low heat for some minutes, keep stirring
If you have some small size bowl or mould, pour into bowls then freeze, nice looking
It's not easy to control the skill on the hardness and softness which  your favorites.
Other options :  sweet corn, green bean, sago.....