I noticed that T likes to figure things out and enjoys games such as the colour sorting, shape sorting, etc... and I really like the serious look on her face when she does them.
2 weeks ago, I invested in a set of the Montessori cylinder blocks as I could think of any homemade toys that can replicate the same effect.(http://www.infomontessori.com/sensorial/visual-sense-cylinder-blocks.htm)
I've only introduced block 1 to T and she's gotten better and faster at it. I might try to introduce block 2 next week.