The Motter Factum combines the functional clarity of a sans serif with the optimal formation of lines of a slab-serif. The order in which the serifs are arranged actually benefits this composition of the letters into homogeneous words, which improves fluent reading. The serifs of the lower back of a letter compliment the serifs of the upper front of the next letter. This interlocking of letters avoids the accumulation of blackening, which is so typical for most bold slab-serif typefaces. This interlocking allows optimal spacing of all weights. Motter Factum is available in 5 weights including italic style. The fonts have been produced by Lucas de Groot , the founder of the thesis type face, according to designs by Othmar Motter.