Filling your stuffs in backpack may be tiring sometimes because your shoulder receive all the impact of the weight. Thanks to the gravity ~ While traveling, the problem gets worst since we need to carry lots of cloths and stuffs.
A way to solve the problem is to use a suitcase with roller wheels. It is convenient for travelers, yet it has its weaknesses. It gets stuck when you are lugging up the staircase. You can't lug the suitcase up the staircase but forced to carry it with your both hands.
Human is intelligent, Woo Moonhyung , he did some little trick with his wisdom and then invented a new roller suitcase - Climbing UP Suitcase , so you can simply lug it up even staircase.
Just a simple trick, magic comes ~
Please do not hesitate to share with me if you do have some invention or idea to tell.