!! used as default html header if there is none in the selected theme.
A triangle has 4 centres: barycenter, orthocenter, incenter and circumcenter.
If you think you know these centers well, try this exercise/game: we show you a triangle, and you should locate one of its centers by shooting on it (click on the picture). Or on the contrary, we show you two of the vertices of the triangle as well as a center, and you shoot on the missing vertex.
Please take note that WIMS pages are interactively generated; they are not ordinary HTML files. They must be used interactively ONLINE. It is useless for you to gather them through a robot program.