Kaminuza ya Leta ya Michigan muri Amerika izwiho uburezi, ubuhinzi n’itumanaho.Ariko abantu bake bazi ko kaminuza imaze imyaka isaga ijana irinda amacupa 20 yikirahure.Aya macupa yakozwe hashize imyaka 137 na Dr. Liam Bill, wagerageje urumamfu mu murima w’ibihingwa.Buri gacupa ryarimo ubwoko 23 bwimbuto z ibihingwa kandi ryashyinguwe mu bice bitandukanye bya kaminuza, hashyizweho itegeko rivuga ko igihe cyose icupa ryakingurwaga, hagomba kubaho imyaka itanu kugirango harebwe niba imbuto zikimera.Kuri iki gipimo, byatwara imyaka 100 yo gufungura amacupa 20 yose.Mu myaka ya za 1920, ubushakashatsi bwafashwe nundi mwarimu, wafashe icyemezo cyo kongera igihe cyo gufungura amacupa kugeza ku myaka 10, kuko ibisubizo byarushijeho kuba byiza kandi imbuto zimwe na zimwe zimera buri gihe.Kubera iyo mpamvu, "umuzamu w'amacupa", Porofeseri Trotsky, yahisemo gufungura amacupa rimwe mu myaka 20.Kuri iki kigero, ubushakashatsi ntibuzarangira byibuze byibuze 2100. Mu birori, inshuti yabajije Trotsky asetsa ati: "Ese ubushakashatsi bwawe n'amacupa 20 yamenetse buracyakwiriye gukorwa?Ntabwo tuzi niba ibisubizo bizagira akamaro! ”“Ntabwo nshobora kubona ibisubizo byanyuma byubushakashatsi.Ariko umuntu ukurikira ushinzwe amacupa rwose azatora igerageza.Nubwo ubu ubushakashatsi bumaze kuba ibisanzwe, mbega ikintu cyiza cyane ko guhitamo kwacu ari ugukomeza kugeza igihe igisubizo kiboneye! ”Trotsky ati.
　　

Ubushakashatsi bumaze ikinyejana, bushobora gusa nubushakashatsi busanzwe, ariko biratangaje kubona ntamuntu numwe, hejuru yabatunze amacupa atabarika, yatekereje ko ari bibi cyangwa ngo abishyire hasi, kandi byakozwe numutwe umwe kugeza uyu munsi .Amacupa 20 yikirahure yerekana umwuka wa kaminuza ya leta ya Michigan - gukomera no gushakisha ukuri.