=== &

Joins (concatenates) the text string yielded by the expression on its left to the text string yielded by the expression on its right.

```
"this is a sentence" & "."
"The problem is:" & space & theProblem
```

=== &&

Joins (concatenates) the text string yielded by the expression on its left to the text string yielded by the expression on its right, with a space between them.

```
"this is" && "sentence."
"card" && the number of this card
```