The decision to exclude visual and demonstrative evidence for irrelevance or undue prejudice is committed almost entirely to the discretion of the trial court.

Fed. R. Evid. 801(a) advisory committee's note ("Similar considerations [considerations simlar to the considerations militating against hearsay treatment of nonassertive nonverbal conduct] govern nonassertive verbal conduct and verbal conduct which is assertive but offered as a basis for inferring something other than the matter...If some human utterance has legal significance under applicable substantive law and the utterance is offered to establish that a verbal act having such legal significance has taken place, the utterance is not hearsay under Federal Rule of Evidence 801(c) or a "statement" for purposes of Federal Rule of Evidence 801(a)(2) even if the utterance also contains an assertion or appears to contain an an assertion.

United States v. Clotida, 892 F.2d 1098, pin? (1st Cir. 1989) (United States v. Clotida, 892 F.2d 1098, 1104 (1st Cir. 1989) ("It cannot be doubted, however, that circumstantial evidence is often very probative. As Professor Wigmore notes, without allowing the introduction...Although proof of criminal guilt can rest on chains of inferences, such pyramided inferences must be reasonable.

Cf. United States v. Washington, 498 F.3d 225, 230-231 (4th Cir. 2007) (upholding trial court's admission of the expert witness's testimony because no out-of-court statement was admitted into evidence through such testimony....A "statement" for purposes of the hearsay prohibition against the admission of hearsay statements is (1) an oral or written assertion or (2) nonverbal conduct of a person, if it is intended by the person as an assertion.