Periwinkle offers a lovely little flower, but it is the leaves and the seeds that are used in folk medicine. The leaves and seeds are rich in the chemical vincamine, an alkaloid that has positive effects on memory and has long been used to combat the effects of aging.eriwinkle is used in folk medicine in the Philippines as a remedy for diabetes. Most of these practices are still followed. Rosy periwinkle grows up to two and a half feet tall. Leaves are oval and have a glossy surface.
C4 envelopes are 229 x 324 mm in size and a A4 card blank can fit inside or an A3 card blank folded in half. These C4 envelopes are ideal for sending A4 documents or certificates. C5 envelopes are 162 x 229 mm in size and fit an A5 card blank or A4 card blank folded in half.
There are a lot of mathematical fomulas behind the workings of A, B and C paper sizes but the underlying feature is that any successive paper size (eg. A1, A2, A3, A4) measurement is determined by halving the dimensions of the preceding one. For example the most commonly used paper size is A4 (297mm x 210mm) and the next paper size is A5 (210mm x 148.5mm) which is equal to half of the A4 dimensions. The main uses of A, B and C paper sizes is their application to a particular print project. For example C paper sizes are solely used for the manufacture of envelopes and are sized in a way that would allow an A4 piece of paper to fit nicely into a C4 envelope.