Pieces doesn't stack after one loop on my connect4

this one helps. Well, for dividing image into pieces you should use the following code (place it in UIImage category):

- (UIImage *)imageCroppedWithRect:(CGRect)rect
{
    if (self.scale > 1.0f) {
        rect = CGRectMake(rect.origin.x * self.scale,
                          rect.origin.y * self.scale,
                          rect.size.width * self.scale,
                          rect.size.height * self.scale);
    }

    CGImageRef imageRef = CGImageCreateWithImageInRect(self.CGImage, rect);
    UIImage *result = [UIImage imageWithCGImage:imageRef scale:self.scale orientation:self.imageOrientation];
    CGImageRelease(imageRef);
    return result;
}

- (void)pieceTapped:(UITapGestureRecognizer *)recognizer
{
    UIImageView *piece = recognizer.view;
    self.zoomedImageView.frame = piece.frame;
    self.zoomedImageView.image = piece.image;
    self.zoomedImageView.hidden = NO;
    [UIView animationWithDuration:0.3 animation:^{
        self.zoomedImageView.frame = self.view.frame;
    }];
}

around this issue Congratulations, you just fell for the fixed limits trap:
You allocate an array of 100 bytes on the stack, then you copy a string of unknown size into it (using strcpy()). Now, when parser is a string that is longer than 100 bytes, strcpy() continues writing past the end of the array, overwriting vital data on your stack, including your functions return address. This is why your program crashes when your function tries to return - it tries to jump to an address that does not exist.

fixed the issue. Will look into that further You could avoid all the Activate and Select and qualify all your Range and Cells statemets inside by using With ws.
So after you loop through all your Worksheets in :

Option Explicit

Sub GetFlows()

Dim cell As Range
Dim dem1 As String
Dim WhereCell As Range
Dim ws As Worksheet

Dim valueRng As Range
Dim x As Long
Dim y As Long

For Each ws In ThisWorkbook.Worksheets
    With ws
        If .Name <> "summary" Then
            For x = 9 To 200 ' run a loop from row 9 to 200
                dem1 = .Range("A" & x).Value

                If dem1 <> "" Then
                    Set WhereCell = .Range("A9:A200").Find(what:=dem1, LookAt:=xlPart)
                    If Not WhereCell Is Nothing Then
                        Workbooks("GetFilenames v2.xlsm").Worksheets(dem1).Range("A1").CurrentRegion.Copy
                        WhereCell.Offset(, 2).PasteSpecial xlPasteValues
                    End If
                End If
            Next x
        End If
    End With
Next ws

End Sub

I think the issue was by ths following , Your constraints are different in these two queries. In the first query, you are applying both constraints to the same language:

language[contains(.,"German") and data(@percentage)>50]

for $p in $doc/countries/country
where $p/language[@percentage >50 and contains(.,"German")]
return $p/@name

To fix this issue I am reading chapter 16 from OSTEP on memory segmentation. ,
in step 4, why is the maximum segment 4KB--isn't it 2KB?