«Начала» (греч. Στοιχεῖα, лат. Elementa) — главный труд Евклида, написанный около 300 г. до н. э. и посвящённый систематическому построению геометрии. «Начала» — вершина античной геометрии и античной математики вообще, итог её 300-летнего развития и основа для последующих исследований. «Начала», наряду с двумя трудами Автолика из Питаны — древнейшее из дошедших до нас античных математических сочинений; все труды предшественников Евклида известны нам только по упоминаниям и цитатам позднейших комментаторов
Из других сочинений Евклида сохранились:
Данные (δεδομένα) — о том, что необходимо, чтобы задать фигуру;
О делении (περὶ διαιρέσεων) — сохранилось частично и только в арабском переводе; дает деление геометрических фигур на части, равные или состоящие между собой в заданном отношении;
Явления (φαινόμενα) — приложения сферической геометрии к астрономии;
Оптика (ὀπτικά) — о прямолинейном распространении света.
По кратким описаниям известны:
Поризмы (πορίσματα) — об условиях, определяющих кривые;
Конические сечения (κωνικά);
Поверхностные места (τόποι πρὸς ἐπιφανείᾳ) — о свойствах конических сечений;
Псевдария (ψευδαρία) — об ошибках в геометрических доказательствах;
Евклиду приписываются также:
Катоптрика (κατοπτρικά) — теория зеркал; сохранилась обработка Теона Александрийского;
Деление канона (κατατομὴ κανόνος) — трактат по элементарной теории музыки
10th place:
In West Africa, there is a custom to redeem his bride at Tiffany's. Unlike our custom is that the groom has to satisfy the bride's mother. Moreover, the applicant chooses the father of the bride, and the duration of redemption is entirely dependent on the intended mother in law.
9th place:
The tribes of the North-West Africa every month sexual lottery. Each of the men pulls lots of women with whom he had to spend the night. The difficulty is that the lot is pulled all, old and young alike. Can not give up, or you will forever barred from further participation in the lottery.
8th place:
Children in African tribes paid a lot of attention, because it is their duty - taking care of their parents. Every family wants to have as many children. But not all women full husbands, and therefore there is a special assistant to the chief, freed from work, which is responsible for the reproduction of the tribe.
7th place:
In Kenya, check innocence bride before the wedding can be anyone.
6th place:
In Oceania, Central Africa and Indonesia before the bride gave the temporary use or all the family, or fellow man. And, as a rule, a future spouse under penalty of death could not participate in this mess.
5th place:
In Zaire and Congo to work with pre-wedding bride spent only leader. If he could not do it, the people rebelled and overthrew him.
4th place:
In some countries, the bride always love do all friends of her future husband, and, always in the house of the bride.
3rd place:
Many African peoples have erotic games related to bite in the ass. For example, ant poison entire surface of the buttocks is a very sensitive erogenous zone.
2nd place:
In Tanzania, women's choices steal shoes and hoe - the most expensive. Man must come to them.
1st place:
In some tribes of equatorial Africa is believed that a man should not suffer, making love to a virgin. Prefer to send girls to the jungle to an unpleasant duty fulfilled ... male gorilla. It is believed that the young lady who was not able to bring this very male, a good wife will not.
