Keystone is the wedge-shaped piece of stone placed at the peak of an arch, which will be the very last piece to be placed during building process and will locks all stones into position making the arch incredibly strong.
how it works
very often, engineers will make the keystone as artistic as possible.
for me, keystone is my feelings and emotions. emotionally unstable, the structure will collapse.
evening run was nice and cooling. it was raining heavily after lunch and I was planning to ride on trainer if the rain doesn't stop. lucky enough, it stopped 15minutes before training. I had Bak Kut Teh and Yau Cha Kuai YESTERDAY! I was expecting poor timing for my weak will to refrain myself from unhealthy food. Somehow, I clocked my personal best just now. 2 minutes faster than my normal time. Isn't that amazing?!