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Visual cryptography (VC) was introduced by Naor and Shamir. In general, a (k, n)-threshold scheme shares a given secret image S among n so-called shadow images. People can "view" the secret image by simply stacking any k of these n shadows (k < n is a threshold value). In most of the reported VC schemes, the size of each shadow is greater than that of S. This paper, we use Hilbert curve and two queues to present a VC scheme with the following properties: (1). Each shadow image is as small as the input image S. (2). Many gracious (k, n) contrast-optimal algorithms can be directly and easily applied to our scheme. (3) Image quality is competitive.