One stroke inserted

What is counted

A pair

B has exactly one more stroke than A. Stroke k of B is not the last stroke. Deleting it leaves a sequence that matches A, stroke for stroke, in order. One pair is one (A, B, k). The same two characters at two indexes would be two pairs.

Stroke distance

The greatest Euclidean distance between corresponding samples, rounded up to a thousandth of a unit. The samples and the threshold are the ones on Order prefixes. Nothing is translated, rotated, scaled, or reflected.

First, early, middle, just before last

N is the stroke count of B. The thirds are the ones already used for stroke length: early when (k−1)×3 is less than (N−1), middle when (k−1)×3 is less than 2(N−1), late otherwise. The four bins are tested in order, and a stroke is counted once. Just before last: k = N−1 and N is at least 3. First: k = 1. Early: the early third, and not one of those two. Middle: every other legal index, including a late stroke that is not the penultimate. When N is 2, the only legal index is 1, and it is first.

Element instance

A g with kvg:element. Groups that carry kvg:part and share kvg:element and kvg:number (empty when the attribute is absent) are one instance. The inserted stroke’s instance is the innermost group. Its other strokes are mapped back onto A by deleting k.

Inside an existing element

Some instance in A has the same kvg:element, and its strokes are exactly those other strokes.

Forms a new element

The instance contains only the inserted stroke. The name may already occur on a different group in A. That is counted separately.

Joins a new element

The instance contains other strokes, and no same-named instance in A has exactly those strokes.

Character group, or nested

Root: the innermost element group has no element group above it. Nested: an element group contains it.

Where the stroke sits

One row is one bin. A pair is in one row. The four rows add to the pair count, including a row whose count is zero.

The inserted stroke’s type

kvg:type of the inserted stroke, as written. A suffix stays in the string. The rows are the strings that occur. They add to the pair count.

Inside an element, or a new one

One row is one relation of the inserted stroke’s element instance to A’s tree. A pair is in one row. Across a row, root and nested add to the total. Down the total column, the three rows add to the pair count.

Whether that name already occurs in A

The same three rows. “Already” means some group in A has that kvg:element string. It does not mean the strokes are the same group. The two columns add to the row.

The threshold

The list, the plates, and the tables above are the primary threshold. The other two rows are the same geometric test. They are not a match on kvg:type.

Plates

A is drawn beside B, each in writing order. Cinnabar marks the inserted stroke of B. A has no such stroke, and it is not recolored. Click a plate to replay. With reduced motion the finished character stays still, and the highlight stays. The plate stays cream in either theme.

• Inserted stroke, cinnabar