Everyone who knits always has a bag full of odds and ends of yarn -- too much to throw away and never quite enough to be of any real use. Potholders are one alternative; doll clothes are another.

But an even better idea is to knit up a pile of basic, 4-inch squares and turn them into a patchwork bedspread. I saw one of these recently on a large brass bed and the effect was absolutely smashing!

There is a lot to be said for afghans and granny squares, of course, but they simply don't work with contemporary furnishings. This does! Amazingly, this chameleon spread manages to take on the look of its surroundings.

It can look like traditional patchwork in an Early American room, yet it takes on the contemporary flavor of a Mondrian painting in a modern setting. Quite a feat, you must admit.

Obviously, you can choose to knit squares in particular colors to go with special decor. Or you can do a crazy quilt to use up all the bits and pieces of yarn on hand.

You could do it with the flat effect of basic knit of stockinette stitch or, if you prefer a textured look, use the purl side. The trick is to make the squares as even and consistent as possible. You might want to make a cardboard test pattern to be sure. Cut this out in graph paper for perfect accuracy and paste it to a cardboard base. Then you can use it for measuring each square to keep them all the exact same size.

Then, using a single crochet stitch, crochet several rows of black around each square until you get a frame that's about 1/2-inch wide. Alternatively, you could use white, or any contrasting color that will hold your whole design together. Lay them out on your bed until you get a pleasing pattern of colors, then join them, either by crocheting or whipping them together with needle and thread.

It's tempting to join them in long strips but I find that unless your squares are exactly the same size (hard to do, since knitting tends to stretch) they may not match when the strips are joined.

Usually, it's better to join squares first in pairs, then in blocks of four, then four of those into a superblock and so on until the spread is completed.

Edge the finished spread with a wider border of black crochet for a tailored effect. Or you might even want to add black fringe. This will have the effect of "framing" your finished spread.

Adding a lining will give you extra warmth and will prevent stretching. Simply sandwich a layer of quality batting between two layers of China silk or soft, non-slip cotton batiste and quilt the knitting and lining together along the outlines of each square.

Q. I have transfer patterns of Pope John Paul II to embroider in cross stitch. It calls for medium weight evenweave fabric, which I can't find anywhere. Can you tell me where I can get it?

A. Instead of asking for "evenweave" fabric, try the trade name: Aida cloth. This means that the fabric has evenly spaced threads, ideal for counted cross stitch. It is available in various weights in cream or white, and if you can't find it at your local needlework store, I suggest you write to Joan Toggitt Ltd., 246 Fifth Ave., New York, N.Y. 10001.

Q. I'm working on a needlepoint that includes metallic thread. I softened the canvas, kept the thread short and yet the thread is cut by the canvas. How can I solve this problem? Also, are there special canvases that include petit point on a needlepoint canvas?

A. You seem to have done all the right things in working with metallic thread. However, I doubt that it is the canvas that is cutting your thread. Frequently the trouble lies in using a needle with too small an eye and this acts as a cutting edge and will snip your thread every time. Use a needle with as large an eye as possible that will go through the mesh.

Most needlework stores carry a European canvas called Penelope which has double threads of canvas forming the mesh. To do larger scale needlepoint (gros point or literally "large stitch") you go over both threads. To do petit point or tiny stitch, you work over each thread individually, thus getting four small stitches in place of one larger needlepoint stitch.