National Council of Teachers of Mathematics
The Math Forum: What Is a Tessellation?
The Math Forum defines and illustrates geometric tessellation.
Oswego City School District
Regents Exam Prep Center: Translations
Explains, with examples, what a translation is. Includes tutorials and practice activities.
University of Kansas Medical Center
Univ. Of Kansas Medical Center: Blood Smear
This site, which is provided for by the University of Kansas Medical Center, gives a microscope slide of Red Blood cells (erythrocytes).
Wolfram Research
Wolfram Math World: Semiregular Tessellations
This one page Mathworld site has a number of examples of semiregular tessellations. A definition and a small amount of related information is given at the bottom of the page.
Math Cats
Math Cats: Visit Tessellation Town on Tile Island!
Go to Tessellation Town on Tile Island and create a variety of tessellations.
Math Is Fun
Math Is Fun: Definition of Congruent
Definition of congruent. Choose the "here's more" link to see examples of a rotation, reflection and translation.
University of Cambridge
University of Cambridge: Nrich: Building Stars
This interactive activity gives you an opportunity to color in a tessellation that is different from the usual. Read the short introduction to find out more about this tessellation that doesn't repeat.
University of Cambridge
University of Cambridge: Nrich: Shapely Tiling
On this one page interactive website expand your logic, Motion Geometry and pattern recognition knowledge while working on this challenge. The solution is available to double check your solution.
Other
Microscope Master: How to Use a Microscope
This website gives detailed step-by-step instructions on how to use and adjust a compound microscope.